Date   

Re: AP1100 Bad Stars Issues

Joe Zeglinski
 

Ray,
 
    On your point of occasionally “seeing east/west side PE”  differences.
 
    Could that be attributed to a minor, possibly intentional,  OTA imbalance causing the worm and worm wheel rubbing on one surface if “pulling” its weight upward, compared, to rubbing on their “opposite faces”,  if holding back the now falling weight of the OTA, on the flip side?
 
    Since even the gear box spur gears aren’t perfect, requiring a PEM correction - should we then assume that BOTH sides of any worm,  or its worm wheel, were cut & ground  perfectly smooth and symmetrical? In the final analysis, there will be at least 6 upto maybe 10 full worm revolutions during a PEM curve creation – and the curve surely would have to be very slightly different, owing to the “directly opposite, east side vs. west side gear faces”  being in contact. Add to that, the mount axle would have been de-clutched and rotated by the user,  at some point in time, so the curve for that test gear section of 6 consecutive worm wheel surfaces,  can change completely.
 
    So, to be closer to perfection, one could consistently choose only one side of the pier in establishing a curve, and redo the curve if the mount is declutched, and repositioned manually, to a different spot on the worm & wheel. But then, the PEM is just an average fix anyway, since if there are worm & wheel surface variations, over a 180 degree span of sky tracking, there will still be spots that don’t quite match the programmed  compensation PEM curve.
 
    End result, I am not surprised in seeing east vs. west side PEM curve differences. Perhaps a separate east & west side run curve could be averaged, in a final PEM curve.
But that’s probably going way over the top.
 
Just a thought.
Joe
 
From: 'Ray Gralak (Groups)' groups3@... [ap-gto]
Sent: Sunday, February 25, 2018 10:15 AM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues
 
Hi Bill,

< SNIP >

I have seen slightly different PE's on each side of the pier with my 1200GTO,
which might have to do with balance.
Best regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro:  http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, February 24, 2018 9:35 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> The image scale was correct. I ran the wizard that set the scale accordingly.
This mount is
> two years old now, so perhaps the error now is what it is. I dont personally
care what it is,
> as long as it can be corrected. What I do care about is being called out for
somehow
> damaging the brand of AP, when in reality what I said was not false at all.
The measured
> error in my mount was close to 9" as I said. Not because I felt it appropriate
to say things
> that were unfounded at all. I didn't spend this kind of money to be treated
like that. Not
> your problem, Ray, you have been very supportive and I appreciate that.
>
>
>
>
> I can image on the east side of the meridian, but in terms of the equator I
have to move
> higher than that in the sky due to trees that block my FOV in the south skies.
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of 'Ray Gralak
> (Groups)' groups3@... [ap-gto]
> Sent: Saturday, February 24, 2018 8:03 PM
> To: ap-gto@...
> Subject: RE: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> Hi Bill,
>
> > While, I do not
> > understand any of this as well as a physicist, is 8.9" of P-P error
> > within
> spec?
>
> If the image scale was incorrect for any reason then the scaling of the curve
would be
> wrong. However, if the created curve removed the periodic error as well as it
looks then
> the periodic error probably was correct.
>
> Looking at the original data it looks like the worm has about 8 arc-secs of PE
and the
> residual is caused by a 4x fundamental. Over time it is likely that the
measured periodic
> error will change, but it usually gets better rather than worse. That said, I
have seen logs
> showing an alarming increase in periodic error in a couple Paramount's that
had heavy
> telescopes mounted on them.
>
> Just out of curiosity can you try measuring PE on East side of the meridian
(with PE
> disabled)?
>
> -Ray Gralak
> Author of APCC (Astro-Physics Command Center):
> http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
> Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM
Driver:
> http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com
Author
> of Sigma: http://www.gralak.com/sigma
>
> > -----Original Message-----
> > From: ap-gto@... [mailto:ap-gto@...]
> > Sent: Saturday, February 24, 2018 5:42 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> > Yeah I did not think that the PEM ON data I had was a good enough set
> > to do
> anything
> > with. Way too limited. That is why I did not try, but I was told to go
> > do some
> simple
> > analysis on it, and that was the only result I could come up with.
> >
> >
> >
> >
> > I did actually walk back through my steps that night I obtained the
> > data,
> which for the
> > record was the first time I have ever used PEMPro. The curve in the
> > mount now,
> was
> > actually inverted. The first test I ran showed 10" of error (you have
> > the logs
> from that, Ray)
> > that's when I inverted the curve and replayed it to the mount. Then I
> > took the
> limited data
> > that is being discussed here, but did not have the boxes checked for
> > drift,
> and saw the 5"
> > of error and assumed I just had bad data and would try again another
> > time. My
> bad.
> > Rookie mistake.
> >
> >
> >
> >
> > Anyhow, I am more than happy to get 4 cycles of data to see how it
> > comes out
> with PEM
> > enabled. I think that is a fair ask and due diligence.
> >
> >
> >
> >
> > Can I ask a question (without my intelligence being attacked again) here?
> While, I do not
> > understand any of this as well as a physicist, is 8.9" of P-P error
> > within
> spec? That is not
> > me trying to be mean, rude, or whatever. Regardless of how well PEMPro
> > can
> correct that,
> > is that legitimate for the product? The sheet I looked at says +/-
> > 3.5" which
> I would assume
> > (again, you guys are the pros, I am the consumer) is 7" P-P.
> >
> >
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > 'Ray Gralak (Groups)' groups3@... [ap-gto]
> >
> > Sent: Saturday, February 24, 2018 5:26 PM
> > To: ap-gto@...
> > Subject: RE: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> > Hi Bill,
> >
> > I don't think that curve is representative if you couldn't use drift
fitting.
> >
> > The data you posted looks like there was virtually no periodic error.
> >
> > -Ray Gralak
> > Author of APCC (Astro-Physics Command Center):
> > http://www.astro-physics.com/index.htm?products/accessories/software/a
> > pcc/apcc Author of PEMPro: http://www.ccdware.com Author of
> > Astro-Physics V2 ASCOM
> Driver:
> > http://www.gralak.com/apdriver Author of PulseGuide:
> > http://www.pulseguide.com
> Author
> > of Sigma: http://www.gralak.com/sigma
> >
> > > -----Original Message-----
> > > From: ap-gto@... [mailto:ap-gto@...]
> > > Sent: Saturday, February 24, 2018 5:13 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > > https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG
> > >
> > >
> > >
> > >
> > > Here is the curve made from the limited PEM ON data.
> > >
> > >
> > >
> > > 2.55 P-P Arc Second. The only drift fitting that showed any error was
"None"
> > though, so I
> > > am not sure how accurate this is.
> > >
> > >
> > > ________________________________
> > >
> > > From: Bill Long
> > > Sent: Saturday, February 24, 2018 3:36 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > > Well, where PEMPro wanted me to point, and stay in the green per the
> > > PEMPro
> > Wizard
> > > was blocked by a tree, so I had to slew a bit further west to get
> > > clear
> skies.
> > Perhaps that
> > > has something to do with the drift?
> > >
> > >
> > >
> > > ________________________________
> > >
> > > From: ap-gto@... on behalf of
> > > chris1011@... [ap-gto]
> > > Sent: Saturday, February 24, 2018 2:35 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > > The curves you posted line up because PEMPro has lined them up for
> > > you when
> > you
> > > clicked on the X and Y alignment tabs. You had mentioned in the
> > > PEMpro
> > postings that
> > > they did not line up and Ray pointed out that you had drift. That
> > > drift is an
> > indication that
> > > your polar alignment is not correct, it shows RA drift. When you
> > > have RA
> > drift, you cannot
> > > expect round stars regardless of mount PE.
> > >
> > >
> > >
> > > I will spend the 30 mins or so to get some fresh PEMPro PE data as
> > > well
> > to see if
> > > there is any difference.
> > >
> > > Why bother, you already have less than 1 arc sec performance. What
> > > do you
> > expect to
> > > achieve with yet another PEMPro run? Your tracking with PEM on is
> > > essentially
> > perfect. If
> > > you do a simple analysis of the PEM on data that you posted, you
> > > will probably
> > find that
> > > the periodic error is on the order of 1/2 arc second. You will not
> > > exceed that
> > and can only
> > > get the same or worse.
> > >
> > > Ray, can you do a quick analysis of that PEM-on run and post the
> > > resultant PE
> > curve?
> > >
> > > Roland Christen
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Bill Long bill@... [ap-gto]
> > > To: ap-gto
> > > Sent: Sat, Feb 24, 2018 3:17 pm
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > The PEM ON test needs to be run still, next clear night I plan to do that.
> > >
> > > When I took my PE data, the curves seem to line up well. Here is
> > > what they
> > looked like:
> > >
> > > https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG
> > >
> > >
> > > Do those look egregious to you?
> > >
> > > As far as Polar Alignment is concerned, I used the Polemaster tool
> > > and ran it
> > through 3
> > > complete cycles to confirm its suggested alignment. Ray suggested I
> > > check that
> > alignment
> > > with PEMPro the next time I am out. I will spend the 30 mins or so
> > > to get some
> > fresh
> > > PEMPro PE data as well to see if there is any difference.
> > > > > > >
> > >
> > >
> > >
> > > ________________________________
> > >
> > > From: ap-gto@... on behalf of
> > > chris1011@... [ap-gto]
> > > Sent: Saturday, February 24, 2018 12:34 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > > What is the PEC curve with PEM turned ON? That is what you will be
> > > using
> > during
> > > tracking.
> > >
> > > When you took your PE data, you said that the individual curves did
> > > not lie on
> > top of each
> > > other, rather they moved up with each new worm cycle. That should
> > > tell you
> > immediately
> > > that your polar alignment is not good, and you have excessive RA
> > > drift. When
> > your polar
> > > alignment is correct (Altitude axis properly aligned), you will
> > > basically have
> > zero RA drift
> > > and each curve will lie on top of the next, or very close to it.
> > > Then with PEM
> > turned on, you
> > > should be able to get no tracking error for several worm cycles when
> > > you are
> > anywhere
> > > near the meridian.
> > >
> > > When you have RA drift, or Dec drift for that matter, you will never
> > > have
> > round stars even
> > > when the mount is tracking to 1 arc sec levels with PEM on. RA drift
> > > is
> > independent of
> > > periodic error and has nothing to do with mount tracking at sidereal
> > > rate. A
> > perfect mount
> > > with zero PE will have egg shaped stars if you have drift in either axis.
> > >
> > > Roland Christen
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Bill Long bill@... [ap-gto]
> > > To: ap-gto
> > > Sent: Sat, Feb 24, 2018 2:16 pm
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG
> > >
> > >
> > >
> > > ________________________________
> > >
> > > From: ap-gto@... on behalf of
> > > chris1011@... [ap-gto]
> >
> > > Sent: Saturday, February 24, 2018 12:07 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > > Maybe I'm missing something, but I see only the raw data, not the PEC
curve.
> > Can you
> > > point it out?
> > >
> > > Rolando
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Bill Long bill@... [ap-gto]
> > >
> > > To: ap-gto
> > > Sent: Sat, Feb 24, 2018 2:04 pm
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > That is all located here:
> > >
> > >
> >
>
http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
> > #50
> > > 87004986
> > >
> > >
> > >
> > >
> > >
> > > ________________________________
> > >
> > > From: ap-gto@... on behalf of
> > > chris1011@... [ap-gto]
> > > Sent: Saturday, February 24, 2018 11:59 AM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > I sent another mail correcting my original statement. I had some
> > > more
> > coffee, then
> > > read it again. Ray had a look at the curve via the PEMPro forums and
> > > I think
> > we are good
> > > to go on that front.
> > >
> > > You posted two raw PEMPro runs, but no analysis of the actual PE
> > > value. Your
> > estimate
> > > of 9 to 10 arc sec P-P is not backed by actual analysis. Please post
> > > the
> > actual PE as
> > > analyzed by PEMPro so that people who read these posts do not get
> > > the false
> > impression
> > > that we ship mounts that are out of spec. The value that defines the
> > > mount's
> > PE is created
> > > when you press the tab "Create a PEC Curve". You will see in the
> > > upper right
> > the value of
> > > the mount's periodic error in +- arc seconds.
> > >
> > > Roland Christen
> > > Astro-Physics Inc.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Bill Long bill@... [ap-gto]
> > >
> > > To: ap-gto <ap-gto@...>
> > > Sent: Sat, Feb 24, 2018 12:52 pm
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > I sent another mail correcting my original statement. I had some
> > > more coffee,
> > then read it
> > > again. Ray had a look at the curve via the PEMPro forums and I think
> > > we are
> > good to go
> > > on that front.
> > >
> > > I will test this again, with PEMPro enabled and guiding running. I
> > > suspect
> > that my results
> > > will be better. Thanks for the info about expectations for
> > > non-guided
> > exposures.
> > >
> > > ________________________________
> > >
> > > From: ap-gto@... on behalf of
> > > chris1011@... [ap-gto] <ap-gto@...>
> > > Sent: Saturday, February 24, 2018 10:44 AM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > The last one I ran was close to 9" P-P. This is almost 3 times the
> > published
> > > specification of +/- 3.5" without any error correction.
> > >
> > > First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9"
> > > P-P is
> > equal to +- 4.5 ".
> > >
> > > I believe you misunderstand what periodic error is and how it is
> > > measured and
> > specified.
> > > A screen capture of the PEMPro run would be helpful, along with the
> > > PEMPro
> > analysis of
> > > Periodic error. Remember, when you are doing a PEMPro run on the
> > > sky, the raw
> > data
> > > also contains errors caused by atmospheric seeing. These can easily
> > > add 3 arc
> > sec or
> > > more to your raw data. PEMPro analysis removes these non-periodic
> > > errors
> > caused by
> > > seeing, drift, etc and provides the true mount tracking performance.
> > >
> > > I saw your images that you sent and they looked normal to me and
> > > George. The
> > 15 sec
> > > images had perfectly round stars, consistent with typical winter seeing.
> > >
> > > I would never expect unguided images to be round for a number of
> > > reasons, none
> > of which
> > > are mount related. In other words, even if the mount tracked
> > > perfectly, I
> > would not expect
> > > round star images in an unguided exposure of any normal length.
> > >
> > > A better indication of performance is the RMS value of your guiding,
> > > using one
> > of the
> > > popular guiding programs (MaximDL or PHD). You can use these
> > > programs to
> > determine
> > > the base level of atmospheric seeing errors and the resultant guided
> > performance in arc
> > > sec RMS. During guiding, when the RMS values of RA and Dec are close
> > > to equal,
> > you
> > > will have round stars on your images.
> > >
> > > Rolando
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Bill Long bill@... [ap-gto]
> > >
> > > To: ap-gto
> > > Sent: Sat, Feb 24, 2018 12:07 pm
> > > Subject: [ap-gto] AP1100 Bad Stars Issues
> > >
> > >
> > >
> > >
> > > Hello all,
> > >
> > > I have contacted A-P about some recent imaging challenges I have
> > > had, and have provided details to George on this problem, but I
> > > wanted to get some thoughts
> > from the
> > > folks here on this forum as well, in the event someone has
> > > experienced a
> > similar problem.
> > >
> > > Problem Statement:
> > > Out of round stars in 15 and 30 second unguided exposures, on two
> > > different
> > cameras.
> > > Out of round Stars in 60 second, 120 second, and 300 second guided
> > > exposures
> > on one
> > > camera.
> > >
> > > Possible Red Herring or Evidence for Concern:
> > > I have run PEMPro and the readings of periodic error are wildly
> inconsistent.
> > I get up to
> > > 10" P-P of RA error. The last one I ran was close to 9" P-P. This is
> > > almost 3
> > times the
> > > published specification of +/- 3.5" without any error correction.
> > >
> > > Polar Alignment Method:
> > > Polemaster, 3 complete cycles per alignment, repeatable results.
> > >
> > > Gear:
> > > Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED
> > > Native w/
> > no
> > > reducer Takahashi TOA130 w/ 0.7x Tak Reducer
> > > AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera
> > > ASI 294MC Pro CMOS Camera
> > >
> > > Software:
> > > APCC Pro
> > > ASCOM v2 AP Driver
> > > Sequence Generator Pro
> > >
> > > All cameras tested were properly spaced on each respective scope. I
> > > have
> > performed
> > > testing with a wheel and OAG attached, as well as without any wheel
> > > or OAG
> > attached,
> > > and spacers in place of them to ensure accurate chip placement.
> > > Using CCDWare
> > CCD
> > > Inspector 2, both cameras are reported to be showing 20% tilt. As a
> > > test, I
> > enabled guiding
> > > and set the RA settings very, very aggressively and while the
> > > problem did not
> > completely
> > > cure itself, the roundness of the stars improved dramatically, and
> > > tilt was
> > reported to be
> > > reduced to 2%.
> > >
> > > The cameras could be involved in the problem, I am not ruling that
> > > out, but to
> > have very
> > > similar results on two different cameras is suspicious, and if there
> > > is a way
> > to rule out the
> > > one constant in all of this testing (the mount) I would like to do that.
> > >
> > > The mount is not permanently mounted. I set up and tear down each
> > > night I
> > image. The
> > > axis are separated and reassembled when the mount goes outside, and
> > > when it
> > comes
> > > back inside each night. In case this information is useful.
> > >
> > > Thanks for reading.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
>



------------------------------------
Posted by: "Ray Gralak \(Groups\)"
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Park on beginning of a session

Stephane Charbonnel
 

Hello,

My question is the opposite of the precedent !
When I stop my session, my planetarium software park the mount at one custom position : the software send pointing at my custom position and after, send park command and as my APCC and AscomV2 is at park = "current position", I can see on the bottom line of APCC : "Parked".
I shutdown APCC then the power of mount.
I have setup my APCC and AscomV2 at : parked = "Last Parked".
When I power the mount at new session, the mount has a speed of 0 : it doesn't move. But when I open APCC, I don't understand why the mount move at sideral speed that is confirmed by message on buttom line : "Unparked".
Please, could you tell the setup I miss ?

Thank you
Stephane


Re: Shutdown APCC

Ray Gralak
 

Hi Stephane,

Thank you for your reply.

It's perfect for auto shutdown.
I'm glad that is what you needed!!

Bets regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 2:19 PM
To: ap-gto@...
Subject: Re: [ap-gto] Shutdown APCC



Ray,


Thank you for your reply.

It's perfect for auto shutdown.

And if I have more opened my eyes, maybe I could see "Ask if OK to Exit". Sorry.


Regards

Stephane


2018-02-24 20:07 GMT+01:00 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-
gto@...>:





Hi Stephane,

> But I would like to know if it exists a command to stop APCC as I click on the
shutdown
> cross at the upper right ? (Not a kill with taskkill but a normal shutdown with
message of
> waiting APCC is shutdown).

I'm not sure if this is what you are asking, but in APCC's Advanced Settings there is
an "Auto Shutdown" option which automatically close APCC after the AP V2 driver
disconnects. For this to work all of the applications using the AP V2 driver must explicitly
disconnect from the driver first.

> An other question : I don't remember how avoid the message of shutdown APCC
(OK /
> Cancel) via the menu File / Exit. Please, could you remember the procedure to
avoid this
> message ?

Uncheck "Ask if OK to Exit" in Program Operation.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-
physics.com/index.htm?products/accessories/software/apcc/apcc <http://www.astro-
physics.com/index.htm?products/accessories/software/apcc/apcc>
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma



> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, February 24, 2018 10:58 AM
> To: ap-gto@...
> Subject: [ap-gto] Shutdown APCC
>
>
>
> Hello,
>
>
> When I run my automatic observatory, at one moment, I power my AP-mount and
then, I
> run the .exe of APCC. All is automatic, driverV2 is automatically running so after,
I connect
> my mount via my planetarium software (http://www.hyperion-astronomy.com/
<http://www.hyperion-astronomy.com/> ).
>
> But I would like to know if it exists a command to stop APCC as I click on the
shutdown
> cross at the upper right ? (Not a kill with taskkill but a normal shutdown with
message of
> waiting APCC is shutdown).
>
> An other question : I don't remember how avoid the message of shutdown APCC
(OK /
> Cancel) via the menu File / Exit. Please, could you remember the procedure to
avoid this
> message ?
>
>
> Regards
>
> Stephane Charbonnel
>
>
>
>







Re: AP1100 Bad Stars Issues

Ray Gralak
 

Hi Bill,

The image scale was correct. I ran the wizard that set the scale accordingly.
This mount is
two years old now, so perhaps the error now is what it is. I dont personally
care what it is,
as long as it can be corrected. What I do care about is being called out for
somehow
damaging the brand of AP, when in reality what I said was not false at all.
The measured
error in my mount was close to 9" as I said. Not because I felt it appropriate
to say things
that were unfounded at all. I didn't spend this kind of money to be treated
like that.

I don't think anything like that was meant. AP performs a very diligent analysis
of every mount's PE before shipping so when an out of spec claim is made I think
it may make AP feel defensive too. And it doesn't help that in the past some
people have not had their image scale set correctly when reporting PEMPro
results!

What I think you should do is run another set of tests with PEM on and off to
confirm what you are seeing. I think that your mount's PE should be easily
corrected with PEMPro, but if you are uncomfortable with the uncorrected PE
value then you should consider giving Howard a call at AP.

Regarding testing on the East side of the mount, that was more of an experiment.
I have seen slightly different PE's on each side of the pier with my 1200GTO,
which might have to do with balance. So, if you better things to do please don't
waste your time on that. Measuring on the West side is usually more convenient
as you don't have a time limit before the mount reaches the meridian.

Best regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 9:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The image scale was correct. I ran the wizard that set the scale accordingly.
This mount is
two years old now, so perhaps the error now is what it is. I dont personally
care what it is,
as long as it can be corrected. What I do care about is being called out for
somehow
damaging the brand of AP, when in reality what I said was not false at all.
The measured
error in my mount was close to 9" as I said. Not because I felt it appropriate
to say things
that were unfounded at all. I didn't spend this kind of money to be treated
like that. Not
your problem, Ray, you have been very supportive and I appreciate that.




I can image on the east side of the meridian, but in terms of the equator I
have to move
higher than that in the sky due to trees that block my FOV in the south skies.



________________________________

From: ap-gto@... <ap-gto@...> on behalf of 'Ray Gralak
(Groups)' groups3@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 8:03 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues



Hi Bill,

While, I do not
understand any of this as well as a physicist, is 8.9" of P-P error
within
spec?

If the image scale was incorrect for any reason then the scaling of the curve
would be
wrong. However, if the created curve removed the periodic error as well as it
looks then
the periodic error probably was correct.

Looking at the original data it looks like the worm has about 8 arc-secs of PE
and the
residual is caused by a 4x fundamental. Over time it is likely that the
measured periodic
error will change, but it usually gets better rather than worse. That said, I
have seen logs
showing an alarming increase in periodic error in a couple Paramount's that
had heavy
telescopes mounted on them.

Just out of curiosity can you try measuring PE on East side of the meridian
(with PE
disabled)?

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM
Driver:
http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com
Author
of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 5:42 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



Yeah I did not think that the PEM ON data I had was a good enough set
to do
anything
with. Way too limited. That is why I did not try, but I was told to go
do some
simple
analysis on it, and that was the only result I could come up with.




I did actually walk back through my steps that night I obtained the
data,
which for the
record was the first time I have ever used PEMPro. The curve in the
mount now,
was
actually inverted. The first test I ran showed 10" of error (you have
the logs
from that, Ray)
that's when I inverted the curve and replayed it to the mount. Then I
took the
limited data
that is being discussed here, but did not have the boxes checked for
drift,
and saw the 5"
of error and assumed I just had bad data and would try again another
time. My
bad.
Rookie mistake.




Anyhow, I am more than happy to get 4 cycles of data to see how it
comes out
with PEM
enabled. I think that is a fair ask and due diligence.




Can I ask a question (without my intelligence being attacked again) here?
While, I do not
understand any of this as well as a physicist, is 8.9" of P-P error
within
spec? That is not
me trying to be mean, rude, or whatever. Regardless of how well PEMPro
can
correct that,
is that legitimate for the product? The sheet I looked at says +/-
3.5" which
I would assume
(again, you guys are the pros, I am the consumer) is 7" P-P.



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
'Ray Gralak (Groups)' groups3@... [ap-gto]
<ap-gto@...>
Sent: Saturday, February 24, 2018 5:26 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues



Hi Bill,

I don't think that curve is representative if you couldn't use drift
fitting.

The data you posted looks like there was virtually no periodic error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/a
pcc/apcc Author of PEMPro: http://www.ccdware.com Author of
Astro-Physics V2 ASCOM
Driver:
http://www.gralak.com/apdriver Author of PulseGuide:
http://www.pulseguide.com
Author
of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 5:13 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG




Here is the curve made from the limited PEM ON data.



2.55 P-P Arc Second. The only drift fitting that showed any error was
"None"
though, so I
am not sure how accurate this is.


________________________________

From: Bill Long <bill@...>
Sent: Saturday, February 24, 2018 3:36 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Well, where PEMPro wanted me to point, and stay in the green per the
PEMPro
Wizard
was blocked by a tree, so I had to slew a bit further west to get
clear
skies.
Perhaps that
has something to do with the drift?



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 2:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The curves you posted line up because PEMPro has lined them up for
you when
you
clicked on the X and Y alignment tabs. You had mentioned in the
PEMpro
postings that
they did not line up and Ray pointed out that you had drift. That
drift is an
indication that
your polar alignment is not correct, it shows RA drift. When you
have RA
drift, you cannot
expect round stars regardless of mount PE.



I will spend the 30 mins or so to get some fresh PEMPro PE data as
well
to see if
there is any difference.

Why bother, you already have less than 1 arc sec performance. What
do you
expect to
achieve with yet another PEMPro run? Your tracking with PEM on is
essentially
perfect. If
you do a simple analysis of the PEM on data that you posted, you
will probably
find that
the periodic error is on the order of 1/2 arc second. You will not
exceed that
and can only
get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the
resultant PE
curve?

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is
what they
looked like:

https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool
and ran it
through 3
complete cycles to confirm its suggested alignment. Ray suggested I
check that
alignment
with PEMPro the next time I am out. I will spend the 30 mins or so
to get some
fresh
PEMPro PE data as well to see if there is any difference.
<https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG


________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


What is the PEC curve with PEM turned ON? That is what you will be
using
during
tracking.

When you took your PE data, you said that the individual curves did
not lie on
top of each
other, rather they moved up with each new worm cycle. That should
tell you
immediately
that your polar alignment is not good, and you have excessive RA
drift. When
your polar
alignment is correct (Altitude axis properly aligned), you will
basically have
zero RA drift
and each curve will lie on top of the next, or very close to it.
Then with PEM
turned on, you
should be able to get no tracking error for several worm cycles when
you are
anywhere
near the meridian.

When you have RA drift, or Dec drift for that matter, you will never
have
round stars even
when the mount is tracking to 1 arc sec levels with PEM on. RA drift
is
independent of
periodic error and has nothing to do with mount tracking at sidereal
rate. A
perfect mount
with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen




-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... <mailto:chris1011@...> [ap-gto]
<ap-gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Maybe I'm missing something, but I see only the raw data, not the PEC
curve.
Can you
point it out?

Rolando




-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




That is all located here:

http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
#50
87004986





________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some
more
coffee, then
read it again. Ray had a look at the curve via the PEMPro forums and
I think
we are good
to go on that front.

You posted two raw PEMPro runs, but no analysis of the actual PE
value. Your
estimate
of 9 to 10 arc sec P-P is not backed by actual analysis. Please post
the
actual PE as
analyzed by PEMPro so that people who read these posts do not get
the false
impression
that we ship mounts that are out of spec. The value that defines the
mount's
PE is created
when you press the tab "Create a PEC Curve". You will see in the
upper right
the value of
the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some
more coffee,
then read it
again. Ray had a look at the curve via the PEMPro forums and I think
we are
good to go
on that front.

I will test this again, with PEMPro enabled and guiding running. I
suspect
that my results
will be better. Thanks for the info about expectations for
non-guided
exposures.

________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The last one I ran was close to 9" P-P. This is almost 3 times the
published
specification of +/- 3.5" without any error correction.

First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9"
P-P is
equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is
measured and
specified.
A screen capture of the PEMPro run would be helpful, along with the
PEMPro
analysis of
Periodic error. Remember, when you are doing a PEMPro run on the
sky, the raw
data
also contains errors caused by atmospheric seeing. These can easily
add 3 arc
sec or
more to your raw data. PEMPro analysis removes these non-periodic
errors
caused by
seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and
George. The
15 sec
images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of
reasons, none
of which
are mount related. In other words, even if the mount tracked
perfectly, I
would not expect
round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding,
using one
of the
popular guiding programs (MaximDL or PHD). You can use these
programs to
determine
the base level of atmospheric seeing errors and the resultant guided
performance in arc
sec RMS. During guiding, when the RMS values of RA and Dec are close
to equal,
you
will have round stars on your images.

Rolando



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues




Hello all,

I have contacted A-P about some recent imaging challenges I have
had, and have provided details to George on this problem, but I
wanted to get some thoughts
from the
folks here on this forum as well, in the event someone has
experienced a
similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two
different
cameras.
Out of round Stars in 60 second, 120 second, and 300 second guided
exposures
on one
camera.

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly
inconsistent.
I get up to
10" P-P of RA error. The last one I ran was close to 9" P-P. This is
almost 3
times the
published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED
Native w/
no
reducer Takahashi TOA130 w/ 0.7x Tak Reducer
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I
have
performed
testing with a wheel and OAG attached, as well as without any wheel
or OAG
attached,
and spacers in place of them to ensure accurate chip placement.
Using CCDWare
CCD
Inspector 2, both cameras are reported to be showing 20% tilt. As a
test, I
enabled guiding
and set the RA settings very, very aggressively and while the
problem did not
completely
cure itself, the roundness of the stars improved dramatically, and
tilt was
reported to be
reduced to 2%.

The cameras could be involved in the problem, I am not ruling that
out, but to
have very
similar results on two different cameras is suspicious, and if there
is a way
to rule out the
one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each
night I
image. The
axis are separated and reassembled when the mount goes outside, and
when it
comes
back inside each night. In case this information is useful.

Thanks for reading.


















Re: AP1100 Bad Stars Issues

Joe Zeglinski
 

Ray,
 
    I’ll just exit here ... by adding that yes, I noticed in my PEM data plots,  that when a star is too dim to be recorded, it doesn’t stop, of course, just seems like the segment does a “straight line” to the next VALID measuring point,  when it is “re-acquired” by the CCD.
I think that’s fair game, hasn’t been an issue. The curve shape gets “dinged” a bit, but over 6 to 10 cycles, its a wash.
 
Thanks,
Joe
 
From: 'Ray Gralak (Groups)' groups3@... [ap-gto]
Sent: Saturday, February 24, 2018 11:09 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues
 
Hi Joe,

>     Wonder if that might be the same case during Bill’s brief PEM  curve test run?

If the brightness goes below a certain level the star is lost and no data point is recorded. I don't see that in Bill's log.

(Also, when acquiring periodic error PEMPro does not try to find another star.)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro:  http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


question on narrowband imaging (calibration)

Suresh Mohan
 

Hello im using astronomik 9nm filters on a colour filter wheel with qhy9 mono camera, whereas the calibration of the Ha appears clean, the O3 looks very funny with some wavy patterns .Is this normal or im doing the calibration wrong?
Suresh


Re: AP1100 Bad Stars Issues

Bill Long
 

The image scale was correct. I ran the wizard that set the scale accordingly. This mount is two years old now, so perhaps the error now is what it is. I dont personally care what it is, as long as it can be corrected. What I do care about is being called out for somehow damaging the brand of AP, when in reality what I said was not false at all. The measured error in my mount was close to 9" as I said. Not because I felt it appropriate to say things that were unfounded at all. I didn't spend this kind of money to be treated like that. Not your problem, Ray, you have been very supportive and I appreciate that.


I can image on the east side of the meridian, but in terms of the equator I have to move higher than that in the sky due to trees that block my FOV in the south skies. 




From: ap-gto@... on behalf of 'Ray Gralak (Groups)' groups3@... [ap-gto]
Sent: Saturday, February 24, 2018 8:03 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues
 
 

Hi Bill,

> While, I do not
> understand any of this as well as a physicist, is 8.9" of P-P error within
spec?

If the image scale was incorrect for any reason then the scaling of the curve
would be wrong. However, if the created curve removed the periodic error as well
as it looks then the periodic error probably was correct.

Looking at the original data it looks like the worm has about 8 arc-secs of PE
and the residual is caused by a 4x fundamental. Over time it is likely that the
measured periodic error will change, but it usually gets better rather than
worse. That said, I have seen logs showing an alarming increase in periodic
error in a couple Paramount's that had heavy telescopes mounted on them.

Just out of curiosity can you try measuring PE on East side of the meridian
(with PE disabled)?

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, February 24, 2018 5:42 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> Yeah I did not think that the PEM ON data I had was a good enough set to do
anything
> with. Way too limited. That is why I did not try, but I was told to go do some
simple
> analysis on it, and that was the only result I could come up with.
>
>
>
>
> I did actually walk back through my steps that night I obtained the data,
which for the
> record was the first time I have ever used PEMPro. The curve in the mount now,
was
> actually inverted. The first test I ran showed 10" of error (you have the logs
from that, Ray)
> that's when I inverted the curve and replayed it to the mount. Then I took the
limited data
> that is being discussed here, but did not have the boxes checked for drift,
and saw the 5"
> of error and assumed I just had bad data and would try again another time. My
bad.
> Rookie mistake.
>
>
>
>
> Anyhow, I am more than happy to get 4 cycles of data to see how it comes out
with PEM
> enabled. I think that is a fair ask and due diligence.
>
>
>
>
> Can I ask a question (without my intelligence being attacked again) here?
While, I do not
> understand any of this as well as a physicist, is 8.9" of P-P error within
spec? That is not
> me trying to be mean, rude, or whatever. Regardless of how well PEMPro can
correct that,
> is that legitimate for the product? The sheet I looked at says +/- 3.5" which
I would assume
> (again, you guys are the pros, I am the consumer) is 7" P-P.
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of 'Ray Gralak
> (Groups)' groups3@... [ap-gto]
> Sent: Saturday, February 24, 2018 5:26 PM
> To: ap-gto@...
> Subject: RE: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> Hi Bill,
>
> I don't think that curve is representative if you couldn't use drift fitting.
>
> The data you posted looks like there was virtually no periodic error.
>
> -Ray Gralak
> Author of APCC (Astro-Physics Command Center):
> http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
> Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM
Driver:
> http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com
Author
> of Sigma: http://www.gralak.com/sigma
>
> > -----Original Message-----
> > From: ap-gto@... [mailto:ap-gto@...]
> > Sent: Saturday, February 24, 2018 5:13 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> > https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG
> >
> >
> >
> >
> > Here is the curve made from the limited PEM ON data.
> >
> >
> >
> > 2.55 P-P Arc Second. The only drift fitting that showed any error was "None"
> though, so I
> > am not sure how accurate this is.
> >
> >
> > ________________________________
> >
> > From: Bill Long
> > Sent: Saturday, February 24, 2018 3:36 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> > Well, where PEMPro wanted me to point, and stay in the green per the
> > PEMPro
> Wizard
> > was blocked by a tree, so I had to slew a bit further west to get clear
skies.
> Perhaps that
> > has something to do with the drift?
> >
> >
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > chris1011@... [ap-gto]
> > Sent: Saturday, February 24, 2018 2:35 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> > The curves you posted line up because PEMPro has lined them up for you
> > when
> you
> > clicked on the X and Y alignment tabs. You had mentioned in the PEMpro
> postings that
> > they did not line up and Ray pointed out that you had drift. That
> > drift is an
> indication that
> > your polar alignment is not correct, it shows RA drift. When you have
> > RA
> drift, you cannot
> > expect round stars regardless of mount PE.
> >
> >
> >
> > I will spend the 30 mins or so to get some fresh PEMPro PE data as
> > well
> to see if
> > there is any difference.
> >
> > Why bother, you already have less than 1 arc sec performance. What do
> > you
> expect to
> > achieve with yet another PEMPro run? Your tracking with PEM on is
> > essentially
> perfect. If
> > you do a simple analysis of the PEM on data that you posted, you will
> > probably
> find that
> > the periodic error is on the order of 1/2 arc second. You will not
> > exceed that
> and can only
> > get the same or worse.
> >
> > Ray, can you do a quick analysis of that PEM-on run and post the
> > resultant PE
> curve?
> >
> > Roland Christen
> >
> >
> >
> > -----Original Message-----
> > From: Bill Long bill@... [ap-gto]
> > To: ap-gto
> > Sent: Sat, Feb 24, 2018 3:17 pm
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > The PEM ON test needs to be run still, next clear night I plan to do that.
> >
> > When I took my PE data, the curves seem to line up well. Here is what
> > they
> looked like:
> >
> > https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG
> >
> >
> > Do those look egregious to you?
> >
> > As far as Polar Alignment is concerned, I used the Polemaster tool and
> > ran it
> through 3
> > complete cycles to confirm its suggested alignment. Ray suggested I
> > check that
> alignment
> > with PEMPro the next time I am out. I will spend the 30 mins or so to
> > get some
> fresh
> > PEMPro PE data as well to see if there is any difference.
> >
> >
> >
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > chris1011@... [ap-gto]
> > Sent: Saturday, February 24, 2018 12:34 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> > What is the PEC curve with PEM turned ON? That is what you will be
> > using
> during
> > tracking.
> >
> > When you took your PE data, you said that the individual curves did
> > not lie on
> top of each
> > other, rather they moved up with each new worm cycle. That should tell
> > you
> immediately
> > that your polar alignment is not good, and you have excessive RA
> > drift. When
> your polar
> > alignment is correct (Altitude axis properly aligned), you will
> > basically have
> zero RA drift
> > and each curve will lie on top of the next, or very close to it. Then
> > with PEM
> turned on, you
> > should be able to get no tracking error for several worm cycles when
> > you are
> anywhere
> > near the meridian.
> >
> > When you have RA drift, or Dec drift for that matter, you will never
> > have
> round stars even
> > when the mount is tracking to 1 arc sec levels with PEM on. RA drift
> > is
> independent of
> > periodic error and has nothing to do with mount tracking at sidereal
> > rate. A
> perfect mount
> > with zero PE will have egg shaped stars if you have drift in either axis.
> >
> > Roland Christen
> >
> >
> >
> >
> > -----Original Message-----
> > From: Bill Long bill@... [ap-gto]
> > To: ap-gto
> > Sent: Sat, Feb 24, 2018 2:16 pm
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG
> >
> >
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > chris1011@... [ap-gto]
>
> > Sent: Saturday, February 24, 2018 12:07 PM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> > Maybe I'm missing something, but I see only the raw data, not the PEC curve.
> Can you
> > point it out?
> >
> > Rolando
> >
> >
> >
> >
> > -----Original Message-----
> > From: Bill Long bill@... [ap-gto]
> >
> > To: ap-gto
> > Sent: Sat, Feb 24, 2018 2:04 pm
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > That is all located here:
> >
> >
>
http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
> #50
> > 87004986
> >
> >
> >
> >
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > chris1011@... [ap-gto]
> > Sent: Saturday, February 24, 2018 11:59 AM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > I sent another mail correcting my original statement. I had some more
> coffee, then
> > read it again. Ray had a look at the curve via the PEMPro forums and I
> > think
> we are good
> > to go on that front.
> >
> > You posted two raw PEMPro runs, but no analysis of the actual PE
> > value. Your
> estimate
> > of 9 to 10 arc sec P-P is not backed by actual analysis. Please post
> > the
> actual PE as
> > analyzed by PEMPro so that people who read these posts do not get the
> > false
> impression
> > that we ship mounts that are out of spec. The value that defines the
> > mount's
> PE is created
> > when you press the tab "Create a PEC Curve". You will see in the upper
> > right
> the value of
> > the mount's periodic error in +- arc seconds.
> >
> > Roland Christen
> > Astro-Physics Inc.
> >
> >
> >
> > -----Original Message-----
> > From: Bill Long bill@... [ap-gto]
> >
> > To: ap-gto <ap-gto@...>
> > Sent: Sat, Feb 24, 2018 12:52 pm
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > I sent another mail correcting my original statement. I had some more
> > coffee,
> then read it
> > again. Ray had a look at the curve via the PEMPro forums and I think
> > we are
> good to go
> > on that front.
> >
> > I will test this again, with PEMPro enabled and guiding running. I
> > suspect
> that my results
> > will be better. Thanks for the info about expectations for non-guided
> exposures.
> >
> > ________________________________
> >
> > From: ap-gto@... on behalf of
> > chris1011@... [ap-gto]
> > Sent: Saturday, February 24, 2018 10:44 AM
> > To: ap-gto@...
> > Subject: Re: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > The last one I ran was close to 9" P-P. This is almost 3 times the
> published
> > specification of +/- 3.5" without any error correction.
> >
> > First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9"
> > P-P is
> equal to +- 4.5 ".
> >
> > I believe you misunderstand what periodic error is and how it is
> > measured and
> specified.
> > A screen capture of the PEMPro run would be helpful, along with the
> > PEMPro
> analysis of
> > Periodic error. Remember, when you are doing a PEMPro run on the sky,
> > the raw
> data
> > also contains errors caused by atmospheric seeing. These can easily
> > add 3 arc
> sec or
> > more to your raw data. PEMPro analysis removes these non-periodic
> > errors
> caused by
> > seeing, drift, etc and provides the true mount tracking performance.
> >
> > I saw your images that you sent and they looked normal to me and
> > George. The
> 15 sec
> > images had perfectly round stars, consistent with typical winter seeing.
> >
> > I would never expect unguided images to be round for a number of
> > reasons, none
> of which
> > are mount related. In other words, even if the mount tracked
> > perfectly, I
> would not expect
> > round star images in an unguided exposure of any normal length.
> >
> > A better indication of performance is the RMS value of your guiding,
> > using one
> of the
> > popular guiding programs (MaximDL or PHD). You can use these programs
> > to
> determine
> > the base level of atmospheric seeing errors and the resultant guided
> performance in arc
> > sec RMS. During guiding, when the RMS values of RA and Dec are close
> > to equal,
> you
> > will have round stars on your images.
> >
> > Rolando
> >
> >
> >
> > -----Original Message-----
> > From: Bill Long bill@... [ap-gto]
> >
> > To: ap-gto
> > Sent: Sat, Feb 24, 2018 12:07 pm
> > Subject: [ap-gto] AP1100 Bad Stars Issues
> >
> >
> >
> >
> > Hello all,
> >
> > I have contacted A-P about some recent imaging challenges I have had,
> > and have provided details to George on this problem, but I wanted to
> > get some thoughts
> from the
> > folks here on this forum as well, in the event someone has experienced
> > a
> similar problem.
> >
> > Problem Statement:
> > Out of round stars in 15 and 30 second unguided exposures, on two
> > different
> cameras.
> > Out of round Stars in 60 second, 120 second, and 300 second guided
> > exposures
> on one
> > camera.
> >
> > Possible Red Herring or Evidence for Concern:
> > I have run PEMPro and the readings of periodic error are wildly
inconsistent.
> I get up to
> > 10" P-P of RA error. The last one I ran was close to 9" P-P. This is
> > almost 3
> times the
> > published specification of +/- 3.5" without any error correction.
> >
> > Polar Alignment Method:
> > Polemaster, 3 complete cycles per alignment, repeatable results.
> >
> > Gear:
> > Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED
> > Native w/
> no
> > reducer Takahashi TOA130 w/ 0.7x Tak Reducer
> > AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera ASI
> > 294MC Pro CMOS Camera
> >
> > Software:
> > APCC Pro
> > ASCOM v2 AP Driver
> > Sequence Generator Pro
> >
> > All cameras tested were properly spaced on each respective scope. I
> > have
> performed
> > testing with a wheel and OAG attached, as well as without any wheel or
> > OAG
> attached,
> > and spacers in place of them to ensure accurate chip placement. Using
> > CCDWare
> CCD
> > Inspector 2, both cameras are reported to be showing 20% tilt. As a
> > test, I
> enabled guiding
> > and set the RA settings very, very aggressively and while the problem
> > did not
> completely
> > cure itself, the roundness of the stars improved dramatically, and
> > tilt was
> reported to be
> > reduced to 2%.
> >
> > The cameras could be involved in the problem, I am not ruling that
> > out, but to
> have very
> > similar results on two different cameras is suspicious, and if there
> > is a way
> to rule out the
> > one constant in all of this testing (the mount) I would like to do that.
> >
> > The mount is not permanently mounted. I set up and tear down each
> > night I
> image. The
> > axis are separated and reassembled when the mount goes outside, and
> > when it
> comes
> > back inside each night. In case this information is useful.
> >
> > Thanks for reading.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>


Re: AP1100 Bad Stars Issues

Ray Gralak
 

Hi Joe,

Wonder if that might be the same case during Bill’s brief PEM curve test run?
If the brightness goes below a certain level the star is lost and no data point is recorded. I don't see that in Bill's log.

(Also, when acquiring periodic error PEMPro does not try to find another star.)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 6:41 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



Ray,

On a few occasions in the past, I would get PERFECT “straight line” AZ-EL graphs
while doing Polar Alignment in PemPro. That seemed to be the case when clouds rolled in
unexpectedly, while I was operating nearby, indoors. I thought it was ideal and far too
good to be true. Under certain conditions, the software doesn’t seem to discriminate, or
warn about diminished, yet not totally lost video signal. However, only a total loss causes
PemPro to search for a new target star. Perhaps I need to raise the “minimum star
magnitude” setting for “observing in the city and suburbs”.

Wonder if that might be the same case during Bill’s brief PEM curve test run?

Joe


Re: AP1100 Bad Stars Issues

Ray Gralak
 

Hi Bill,

While, I do not
understand any of this as well as a physicist, is 8.9" of P-P error within
spec?

If the image scale was incorrect for any reason then the scaling of the curve
would be wrong. However, if the created curve removed the periodic error as well
as it looks then the periodic error probably was correct.

Looking at the original data it looks like the worm has about 8 arc-secs of PE
and the residual is caused by a 4x fundamental. Over time it is likely that the
measured periodic error will change, but it usually gets better rather than
worse. That said, I have seen logs showing an alarming increase in periodic
error in a couple Paramount's that had heavy telescopes mounted on them.

Just out of curiosity can you try measuring PE on East side of the meridian
(with PE disabled)?

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 5:42 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



Yeah I did not think that the PEM ON data I had was a good enough set to do
anything
with. Way too limited. That is why I did not try, but I was told to go do some
simple
analysis on it, and that was the only result I could come up with.




I did actually walk back through my steps that night I obtained the data,
which for the
record was the first time I have ever used PEMPro. The curve in the mount now,
was
actually inverted. The first test I ran showed 10" of error (you have the logs
from that, Ray)
that's when I inverted the curve and replayed it to the mount. Then I took the
limited data
that is being discussed here, but did not have the boxes checked for drift,
and saw the 5"
of error and assumed I just had bad data and would try again another time. My
bad.
Rookie mistake.




Anyhow, I am more than happy to get 4 cycles of data to see how it comes out
with PEM
enabled. I think that is a fair ask and due diligence.




Can I ask a question (without my intelligence being attacked again) here?
While, I do not
understand any of this as well as a physicist, is 8.9" of P-P error within
spec? That is not
me trying to be mean, rude, or whatever. Regardless of how well PEMPro can
correct that,
is that legitimate for the product? The sheet I looked at says +/- 3.5" which
I would assume
(again, you guys are the pros, I am the consumer) is 7" P-P.



________________________________

From: ap-gto@... <ap-gto@...> on behalf of 'Ray Gralak
(Groups)' groups3@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 5:26 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues



Hi Bill,

I don't think that curve is representative if you couldn't use drift fitting.

The data you posted looks like there was virtually no periodic error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM
Driver:
http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com
Author
of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 5:13 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG




Here is the curve made from the limited PEM ON data.



2.55 P-P Arc Second. The only drift fitting that showed any error was "None"
though, so I
am not sure how accurate this is.


________________________________

From: Bill Long <bill@...>
Sent: Saturday, February 24, 2018 3:36 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Well, where PEMPro wanted me to point, and stay in the green per the
PEMPro
Wizard
was blocked by a tree, so I had to slew a bit further west to get clear
skies.
Perhaps that
has something to do with the drift?



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 2:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The curves you posted line up because PEMPro has lined them up for you
when
you
clicked on the X and Y alignment tabs. You had mentioned in the PEMpro
postings that
they did not line up and Ray pointed out that you had drift. That
drift is an
indication that
your polar alignment is not correct, it shows RA drift. When you have
RA
drift, you cannot
expect round stars regardless of mount PE.



I will spend the 30 mins or so to get some fresh PEMPro PE data as
well
to see if
there is any difference.

Why bother, you already have less than 1 arc sec performance. What do
you
expect to
achieve with yet another PEMPro run? Your tracking with PEM on is
essentially
perfect. If
you do a simple analysis of the PEM on data that you posted, you will
probably
find that
the periodic error is on the order of 1/2 arc second. You will not
exceed that
and can only
get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the
resultant PE
curve?

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is what
they
looked like:

https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool and
ran it
through 3
complete cycles to confirm its suggested alignment. Ray suggested I
check that
alignment
with PEMPro the next time I am out. I will spend the 30 mins or so to
get some
fresh
PEMPro PE data as well to see if there is any difference.
<https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG>



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


What is the PEC curve with PEM turned ON? That is what you will be
using
during
tracking.

When you took your PE data, you said that the individual curves did
not lie on
top of each
other, rather they moved up with each new worm cycle. That should tell
you
immediately
that your polar alignment is not good, and you have excessive RA
drift. When
your polar
alignment is correct (Altitude axis properly aligned), you will
basically have
zero RA drift
and each curve will lie on top of the next, or very close to it. Then
with PEM
turned on, you
should be able to get no tracking error for several worm cycles when
you are
anywhere
near the meridian.

When you have RA drift, or Dec drift for that matter, you will never
have
round stars even
when the mount is tracking to 1 arc sec levels with PEM on. RA drift
is
independent of
periodic error and has nothing to do with mount tracking at sidereal
rate. A
perfect mount
with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen




-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... <mailto:chris1011@...> [ap-gto]
<ap-gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Maybe I'm missing something, but I see only the raw data, not the PEC curve.
Can you
point it out?

Rolando




-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




That is all located here:

http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
#50
87004986





________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some more
coffee, then
read it again. Ray had a look at the curve via the PEMPro forums and I
think
we are good
to go on that front.

You posted two raw PEMPro runs, but no analysis of the actual PE
value. Your
estimate
of 9 to 10 arc sec P-P is not backed by actual analysis. Please post
the
actual PE as
analyzed by PEMPro so that people who read these posts do not get the
false
impression
that we ship mounts that are out of spec. The value that defines the
mount's
PE is created
when you press the tab "Create a PEC Curve". You will see in the upper
right
the value of
the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some more
coffee,
then read it
again. Ray had a look at the curve via the PEMPro forums and I think
we are
good to go
on that front.

I will test this again, with PEMPro enabled and guiding running. I
suspect
that my results
will be better. Thanks for the info about expectations for non-guided
exposures.

________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The last one I ran was close to 9" P-P. This is almost 3 times the
published
specification of +/- 3.5" without any error correction.

First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9"
P-P is
equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is
measured and
specified.
A screen capture of the PEMPro run would be helpful, along with the
PEMPro
analysis of
Periodic error. Remember, when you are doing a PEMPro run on the sky,
the raw
data
also contains errors caused by atmospheric seeing. These can easily
add 3 arc
sec or
more to your raw data. PEMPro analysis removes these non-periodic
errors
caused by
seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and
George. The
15 sec
images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of
reasons, none
of which
are mount related. In other words, even if the mount tracked
perfectly, I
would not expect
round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding,
using one
of the
popular guiding programs (MaximDL or PHD). You can use these programs
to
determine
the base level of atmospheric seeing errors and the resultant guided
performance in arc
sec RMS. During guiding, when the RMS values of RA and Dec are close
to equal,
you
will have round stars on your images.

Rolando



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto]
<ap- gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues




Hello all,

I have contacted A-P about some recent imaging challenges I have had,
and have provided details to George on this problem, but I wanted to
get some thoughts
from the
folks here on this forum as well, in the event someone has experienced
a
similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two
different
cameras.
Out of round Stars in 60 second, 120 second, and 300 second guided
exposures
on one
camera.

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly
inconsistent.
I get up to
10" P-P of RA error. The last one I ran was close to 9" P-P. This is
almost 3
times the
published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED
Native w/
no
reducer Takahashi TOA130 w/ 0.7x Tak Reducer
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera ASI
294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I
have
performed
testing with a wheel and OAG attached, as well as without any wheel or
OAG
attached,
and spacers in place of them to ensure accurate chip placement. Using
CCDWare
CCD
Inspector 2, both cameras are reported to be showing 20% tilt. As a
test, I
enabled guiding
and set the RA settings very, very aggressively and while the problem
did not
completely
cure itself, the roundness of the stars improved dramatically, and
tilt was
reported to be
reduced to 2%.

The cameras could be involved in the problem, I am not ruling that
out, but to
have very
similar results on two different cameras is suspicious, and if there
is a way
to rule out the
one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each
night I
image. The
axis are separated and reassembled when the mount goes outside, and
when it
comes
back inside each night. In case this information is useful.

Thanks for reading.
















Re: AP1100 Bad Stars Issues

Joe Zeglinski
 

Ray,
 
    On a few occasions in the past, I would get PERFECT  “straight line”  AZ-EL graphs while doing Polar Alignment in PemPro. That seemed to be the case when clouds rolled in unexpectedly, while I was operating nearby,  indoors. I thought it was ideal and far too good to be true. Under certain conditions, the software doesn’t seem to discriminate, or warn about diminished,  yet not totally lost video signal. However, only a total loss causes PemPro to search for a new target star. Perhaps I need to raise the “minimum star magnitude” setting for  “observing in the city and suburbs”.
 
    Wonder if that might be the same case during Bill’s brief PEM  curve test run?
 
Joe


Re: AP1100 Bad Stars Issues

Bill Long
 

Yeah I did not think that the PEM ON data I had was a good enough set to do anything with. Way too limited. That is why I did not try, but I was told to go do some simple analysis on it, and that was the only result I could come up with. 


I did actually walk back through my steps that night I obtained the data, which for the record was the first time I have ever used PEMPro. The curve in the mount now, was actually inverted. The first test I ran showed 10" of error (you have the logs from that, Ray) that's when I inverted the curve and replayed it to the mount. Then I took the limited data that is being discussed here, but did not have the boxes checked for drift, and saw the 5" of error and assumed I just had bad data and would try again another time. My bad. Rookie mistake.


Anyhow, I am more than happy to get 4 cycles of data to see how it comes out with PEM enabled. I think that is a fair ask and due diligence.


Can I ask a question (without my intelligence being attacked again) here? While, I do not understand any of this as well as a physicist, is 8.9" of P-P error within spec? That is not me trying to be mean, rude, or whatever. Regardless of how well PEMPro can correct that, is that legitimate for the product? The sheet I looked at says +/- 3.5" which I would assume (again, you guys are the pros, I am the consumer) is 7" P-P.




From: ap-gto@... on behalf of 'Ray Gralak (Groups)' groups3@... [ap-gto]
Sent: Saturday, February 24, 2018 5:26 PM
To: ap-gto@...
Subject: RE: [ap-gto] AP1100 Bad Stars Issues
 
 

Hi Bill,

I don't think that curve is representative if you couldn't use drift fitting.

The data you posted looks like there was virtually no periodic error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, February 24, 2018 5:13 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG
>
>
>
>
> Here is the curve made from the limited PEM ON data.
>
>
>
> 2.55 P-P Arc Second. The only drift fitting that showed any error was "None"
though, so I
> am not sure how accurate this is.
>
>
> ________________________________
>
> From: Bill Long
> Sent: Saturday, February 24, 2018 3:36 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
> Well, where PEMPro wanted me to point, and stay in the green per the PEMPro
Wizard
> was blocked by a tree, so I had to slew a bit further west to get clear skies.
Perhaps that
> has something to do with the drift?
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of
> chris1011@... [ap-gto]
> Sent: Saturday, February 24, 2018 2:35 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
> The curves you posted line up because PEMPro has lined them up for you when
you
> clicked on the X and Y alignment tabs. You had mentioned in the PEMpro
postings that
> they did not line up and Ray pointed out that you had drift. That drift is an
indication that
> your polar alignment is not correct, it shows RA drift. When you have RA
drift, you cannot
> expect round stars regardless of mount PE.
>
>
>
> I will spend the 30 mins or so to get some fresh PEMPro PE data as well
to see if
> there is any difference.
>
> Why bother, you already have less than 1 arc sec performance. What do you
expect to
> achieve with yet another PEMPro run? Your tracking with PEM on is essentially
perfect. If
> you do a simple analysis of the PEM on data that you posted, you will probably
find that
> the periodic error is on the order of 1/2 arc second. You will not exceed that
and can only
> get the same or worse.
>
> Ray, can you do a quick analysis of that PEM-on run and post the resultant PE
curve?
>
> Roland Christen
>
>
>
> -----Original Message-----
> From: Bill Long bill@... [ap-gto]
> To: ap-gto
> Sent: Sat, Feb 24, 2018 3:17 pm
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> The PEM ON test needs to be run still, next clear night I plan to do that.
>
> When I took my PE data, the curves seem to line up well. Here is what they
looked like:
>
> https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG
>
>
> Do those look egregious to you?
>
> As far as Polar Alignment is concerned, I used the Polemaster tool and ran it
through 3
> complete cycles to confirm its suggested alignment. Ray suggested I check that
alignment
> with PEMPro the next time I am out. I will spend the 30 mins or so to get some
fresh
> PEMPro PE data as well to see if there is any difference.
>
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of
> chris1011@... [ap-gto]
> Sent: Saturday, February 24, 2018 12:34 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
> What is the PEC curve with PEM turned ON? That is what you will be using
during
> tracking.
>
> When you took your PE data, you said that the individual curves did not lie on
top of each
> other, rather they moved up with each new worm cycle. That should tell you
immediately
> that your polar alignment is not good, and you have excessive RA drift. When
your polar
> alignment is correct (Altitude axis properly aligned), you will basically have
zero RA drift
> and each curve will lie on top of the next, or very close to it. Then with PEM
turned on, you
> should be able to get no tracking error for several worm cycles when you are
anywhere
> near the meridian.
>
> When you have RA drift, or Dec drift for that matter, you will never have
round stars even
> when the mount is tracking to 1 arc sec levels with PEM on. RA drift is
independent of
> periodic error and has nothing to do with mount tracking at sidereal rate. A
perfect mount
> with zero PE will have egg shaped stars if you have drift in either axis.
>
> Roland Christen
>
>
>
>
> -----Original Message-----
> From: Bill Long bill@... [ap-gto]
> To: ap-gto
> Sent: Sat, Feb 24, 2018 2:16 pm
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of
> chris1011@... <mailto:chris1011@...> [ap-gto]

> Sent: Saturday, February 24, 2018 12:07 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
> Maybe I'm missing something, but I see only the raw data, not the PEC curve.
Can you
> point it out?
>
> Rolando
>
>
>
>
> -----Original Message-----
> From: Bill Long bill@... [ap-gto] > gto@...>
> To: ap-gto
> Sent: Sat, Feb 24, 2018 2:04 pm
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> That is all located here:
>
>
http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
#50
> 87004986
>
>
>
>
>
> ________________________________
>
> From: ap-gto@... on behalf of
> chris1011@... [ap-gto]
> Sent: Saturday, February 24, 2018 11:59 AM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> I sent another mail correcting my original statement. I had some more
coffee, then
> read it again. Ray had a look at the curve via the PEMPro forums and I think
we are good
> to go on that front.
>
> You posted two raw PEMPro runs, but no analysis of the actual PE value. Your
estimate
> of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the
actual PE as
> analyzed by PEMPro so that people who read these posts do not get the false
impression
> that we ship mounts that are out of spec. The value that defines the mount's
PE is created
> when you press the tab "Create a PEC Curve". You will see in the upper right
the value of
> the mount's periodic error in +- arc seconds.
>
> Roland Christen
> Astro-Physics Inc.
>
>
>
> -----Original Message-----
> From: Bill Long bill@... [ap-gto] <ap-
> gto@...>
> To: ap-gto
> Sent: Sat, Feb 24, 2018 12:52 pm
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> I sent another mail correcting my original statement. I had some more coffee,
then read it
> again. Ray had a look at the curve via the PEMPro forums and I think we are
good to go
> on that front.
>
> I will test this again, with PEMPro enabled and guiding running. I suspect
that my results
> will be better. Thanks for the info about expectations for non-guided
exposures.
>
> ________________________________
>
> From: ap-gto@... on behalf of
> chris1011@... [ap-gto]
> Sent: Saturday, February 24, 2018 10:44 AM
> To: ap-gto@...
> Subject: Re: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> The last one I ran was close to 9" P-P. This is almost 3 times the
published
> specification of +/- 3.5" without any error correction.
>
> First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is
equal to +- 4.5 ".
>
> I believe you misunderstand what periodic error is and how it is measured and
specified.
> A screen capture of the PEMPro run would be helpful, along with the PEMPro
analysis of
> Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw
data
> also contains errors caused by atmospheric seeing. These can easily add 3 arc
sec or
> more to your raw data. PEMPro analysis removes these non-periodic errors
caused by
> seeing, drift, etc and provides the true mount tracking performance.
>
> I saw your images that you sent and they looked normal to me and George. The
15 sec
> images had perfectly round stars, consistent with typical winter seeing.
>
> I would never expect unguided images to be round for a number of reasons, none
of which
> are mount related. In other words, even if the mount tracked perfectly, I
would not expect
> round star images in an unguided exposure of any normal length.
>
> A better indication of performance is the RMS value of your guiding, using one
of the
> popular guiding programs (MaximDL or PHD). You can use these programs to
determine
> the base level of atmospheric seeing errors and the resultant guided
performance in arc
> sec RMS. During guiding, when the RMS values of RA and Dec are close to equal,
you
> will have round stars on your images.
>
> Rolando
>
>
>
> -----Original Message-----
> From: Bill Long bill@... [ap-gto] > gto@...>
> To: ap-gto
> Sent: Sat, Feb 24, 2018 12:07 pm
> Subject: [ap-gto] AP1100 Bad Stars Issues
>
>
>
>
> Hello all,
>
> I have contacted A-P about some recent imaging challenges I have had, and have
> provided details to George on this problem, but I wanted to get some thoughts
from the
> folks here on this forum as well, in the event someone has experienced a
similar problem.
>
> Problem Statement:
> Out of round stars in 15 and 30 second unguided exposures, on two different
cameras.
> Out of round Stars in 60 second, 120 second, and 300 second guided exposures
on one
> camera.
>
> Possible Red Herring or Evidence for Concern:
> I have run PEMPro and the readings of periodic error are wildly inconsistent.
I get up to
> 10" P-P of RA error. The last one I ran was close to 9" P-P. This is almost 3
times the
> published specification of +/- 3.5" without any error correction.
>
> Polar Alignment Method:
> Polemaster, 3 complete cycles per alignment, repeatable results.
>
> Gear:
> Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED Native w/
no
> reducer Takahashi TOA130 w/ 0.7x Tak Reducer
> AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera ASI
> 294MC Pro CMOS Camera
>
> Software:
> APCC Pro
> ASCOM v2 AP Driver
> Sequence Generator Pro
>
> All cameras tested were properly spaced on each respective scope. I have
performed
> testing with a wheel and OAG attached, as well as without any wheel or OAG
attached,
> and spacers in place of them to ensure accurate chip placement. Using CCDWare
CCD
> Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I
enabled guiding
> and set the RA settings very, very aggressively and while the problem did not
completely
> cure itself, the roundness of the stars improved dramatically, and tilt was
reported to be
> reduced to 2%.
>
> The cameras could be involved in the problem, I am not ruling that out, but to
have very
> similar results on two different cameras is suspicious, and if there is a way
to rule out the
> one constant in all of this testing (the mount) I would like to do that.
>
> The mount is not permanently mounted. I set up and tear down each night I
image. The
> axis are separated and reassembled when the mount goes outside, and when it
comes
> back inside each night. In case this information is useful.
>
> Thanks for reading.
>
>
>
>
>
>
>
>
>
>
>
>
>
>


Re: AP1100 Bad Stars Issues

Ray Gralak
 

Hi Bill,

I don't think that curve is representative if you couldn't use drift fitting.

The data you posted looks like there was virtually no periodic error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center):
http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, February 24, 2018 5:13 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG




Here is the curve made from the limited PEM ON data.



2.55 P-P Arc Second. The only drift fitting that showed any error was "None"
though, so I
am not sure how accurate this is.


________________________________

From: Bill Long <bill@...>
Sent: Saturday, February 24, 2018 3:36 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Well, where PEMPro wanted me to point, and stay in the green per the PEMPro
Wizard
was blocked by a tree, so I had to slew a bit further west to get clear skies.
Perhaps that
has something to do with the drift?



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 2:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The curves you posted line up because PEMPro has lined them up for you when
you
clicked on the X and Y alignment tabs. You had mentioned in the PEMpro
postings that
they did not line up and Ray pointed out that you had drift. That drift is an
indication that
your polar alignment is not correct, it shows RA drift. When you have RA
drift, you cannot
expect round stars regardless of mount PE.



I will spend the 30 mins or so to get some fresh PEMPro PE data as well
to see if
there is any difference.

Why bother, you already have less than 1 arc sec performance. What do you
expect to
achieve with yet another PEMPro run? Your tracking with PEM on is essentially
perfect. If
you do a simple analysis of the PEM on data that you posted, you will probably
find that
the periodic error is on the order of 1/2 arc second. You will not exceed that
and can only
get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the resultant PE
curve?

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is what they
looked like:

https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool and ran it
through 3
complete cycles to confirm its suggested alignment. Ray suggested I check that
alignment
with PEMPro the next time I am out. I will spend the 30 mins or so to get some
fresh
PEMPro PE data as well to see if there is any difference.
<https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG>



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


What is the PEC curve with PEM turned ON? That is what you will be using
during
tracking.

When you took your PE data, you said that the individual curves did not lie on
top of each
other, rather they moved up with each new worm cycle. That should tell you
immediately
that your polar alignment is not good, and you have excessive RA drift. When
your polar
alignment is correct (Altitude axis properly aligned), you will basically have
zero RA drift
and each curve will lie on top of the next, or very close to it. Then with PEM
turned on, you
should be able to get no tracking error for several worm cycles when you are
anywhere
near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have
round stars even
when the mount is tracking to 1 arc sec levels with PEM on. RA drift is
independent of
periodic error and has nothing to do with mount tracking at sidereal rate. A
perfect mount
with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen




-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro_Curve.JPG



________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... <mailto:chris1011@...> [ap-gto]
<ap-gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues


Maybe I'm missing something, but I see only the raw data, not the PEC curve.
Can you
point it out?

Rolando




-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto] <ap-
gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




That is all located here:

http://ccdware.infopop.cc/eve/forums/a/tpc/f/401101098/m/8577004986?r=5087004986
#50
87004986





________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some more
coffee, then
read it again. Ray had a look at the curve via the PEMPro forums and I think
we are good
to go on that front.

You posted two raw PEMPro runs, but no analysis of the actual PE value. Your
estimate
of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the
actual PE as
analyzed by PEMPro so that people who read these posts do not get the false
impression
that we ship mounts that are out of spec. The value that defines the mount's
PE is created
when you press the tab "Create a PEC Curve". You will see in the upper right
the value of
the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto] <ap-
gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




I sent another mail correcting my original statement. I had some more coffee,
then read it
again. Ray had a look at the curve via the PEMPro forums and I think we are
good to go
on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect
that my results
will be better. Thanks for the info about expectations for non-guided
exposures.

________________________________

From: ap-gto@... <ap-gto@...> on behalf of
chris1011@... [ap-gto] <ap-gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues




The last one I ran was close to 9" P-P. This is almost 3 times the
published
specification of +/- 3.5" without any error correction.

First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is
equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and
specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro
analysis of
Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw
data
also contains errors caused by atmospheric seeing. These can easily add 3 arc
sec or
more to your raw data. PEMPro analysis removes these non-periodic errors
caused by
seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The
15 sec
images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none
of which
are mount related. In other words, even if the mount tracked perfectly, I
would not expect
round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one
of the
popular guiding programs (MaximDL or PHD). You can use these programs to
determine
the base level of atmospheric seeing errors and the resultant guided
performance in arc
sec RMS. During guiding, when the RMS values of RA and Dec are close to equal,
you
will have round stars on your images.

Rolando



-----Original Message-----
From: Bill Long bill@... <mailto:bill@...> [ap-gto] <ap-
gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues




Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have
provided details to George on this problem, but I wanted to get some thoughts
from the
folks here on this forum as well, in the event someone has experienced a
similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different
cameras.
Out of round Stars in 60 second, 120 second, and 300 second guided exposures
on one
camera.

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent.
I get up to
10" P-P of RA error. The last one I ran was close to 9" P-P. This is almost 3
times the
published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener Takahashi FSQ106ED Native w/
no
reducer Takahashi TOA130 w/ 0.7x Tak Reducer
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox ASI 183MM Pro CMOS Camera ASI
294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have
performed
testing with a wheel and OAG attached, as well as without any wheel or OAG
attached,
and spacers in place of them to ensure accurate chip placement. Using CCDWare
CCD
Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I
enabled guiding
and set the RA settings very, very aggressively and while the problem did not
completely
cure itself, the roundness of the stars improved dramatically, and tilt was
reported to be
reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to
have very
similar results on two different cameras is suspicious, and if there is a way
to rule out the
one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I
image. The
axis are separated and reassembled when the mount goes outside, and when it
comes
back inside each night. In case this information is useful.

Thanks for reading.














Re: AP1100 Bad Stars Issues

Bill Long
 

https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG


Here is the curve made from the limited PEM ON data. 


2.55 P-P Arc Second. The only drift fitting that showed any error was "None" though, so I am not sure how accurate this is.


From: Bill Long
Sent: Saturday, February 24, 2018 3:36 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 

Well, where PEMPro wanted me to point, and stay in the green per the PEMPro Wizard was blocked by a tree, so I had to slew a bit further west to get clear skies. Perhaps that has something to do with the drift?




From: ap-gto@... on behalf of chris1011@... [ap-gto]
Sent: Saturday, February 24, 2018 2:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The curves you posted line up because PEMPro has lined them up for you when you clicked on the X and Y alignment tabs. You had mentioned in the PEMpro postings that they did not line up and Ray pointed out that you had drift. That drift is an indication that your polar alignment is not correct, it shows RA drift. When you have RA drift, you cannot expect round stars regardless of mount PE.


I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.
Why bother, you already have less than 1 arc sec performance. What do you expect to achieve with yet another PEMPro run? Your tracking with PEM on is essentially perfect. If you do a simple analysis of the PEM on data that you posted, you will probably find that the periodic error is on the order of 1/2 arc second. You will not exceed that and can only get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the resultant PE curve?

Roland Christen


-----Original Message-----
From: Bill Long bill@... [ap-gto]
To: ap-gto
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is what they looked like:


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool and ran it through 3 complete cycles to confirm its suggested alignment. Ray suggested I check that alignment with PEMPro the next time I am out. I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.




From: ap-gto@... <ap-gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
What is the PEC curve with PEM turned ON? That is what you will be using during tracking.

When you took your PE data, you said that the individual curves did not lie on top of each other, rather they moved up with each new worm cycle. That should tell you immediately that your polar alignment is not good, and you have excessive RA drift. When your polar alignment is correct (Altitude axis properly aligned), you will basically have zero RA drift and each curve will lie on top of the next, or very close to it. Then with PEM turned on, you should be able to get no tracking error for several worm cycles when you are anywhere near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have round stars even when the mount is tracking to 1 arc sec levels with PEM on. RA drift is independent of periodic error and has nothing to do with mount tracking at sidereal rate. A perfect mount with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues







From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
Maybe I'm missing something, but I see only the raw data, not the PEC curve. Can you point it out?

Rolando



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



That is all located here:






From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.
You posted two raw PEMPro runs, but no analysis of the actual PE value. Your estimate of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the actual PE as analyzed by PEMPro so that people who read these posts do not get the false impression that we ship mounts that are out of spec. The value that defines the mount's PE is created when you press the tab "Create a PEC Curve". You will see in the upper right the value of the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect that my results will be better. Thanks for the info about expectations for non-guided exposures. 


From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.
First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro analysis of Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw data also contains errors caused by atmospheric seeing. These can easily add 3 arc sec or more to your raw data. PEMPro analysis removes these non-periodic errors caused by seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The 15 sec images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none of which are mount related. In other words, even if the mount tracked perfectly, I would not expect round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one of the popular guiding programs (MaximDL or PHD). You can use these programs to determine the base level of atmospheric seeing errors and the resultant guided performance in arc sec RMS. During guiding, when the RMS values of RA and Dec are close to equal, you will have round stars on your images.

Rolando


-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues



Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have provided details to George on this problem, but I wanted to get some thoughts from the folks here on this forum as well, in the event someone has experienced a similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different cameras. 
Out of round Stars in 60 second, 120 second, and 300 second guided exposures on one camera. 

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent. I get up to 10" P-P of RA error. The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener
Takahashi FSQ106ED Native w/ no reducer
Takahashi TOA130 w/ 0.7x Tak Reducer 
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox
ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have performed testing with a wheel and OAG attached, as well as without any wheel or OAG attached, and spacers in place of them to ensure accurate chip placement. Using CCDWare CCD Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I enabled guiding and set the RA settings very, very aggressively and while the problem did not completely cure itself, the roundness of the stars improved dramatically, and tilt was reported to be reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to have very similar results on two different cameras is suspicious, and if there is a way to rule out the one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I image. The axis are separated and reassembled when the mount goes outside, and when it comes back inside each night.  In case this information is useful.

Thanks for reading.













New file uploaded to ap-gto

ap-gto@...
 

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the ap-gto
group.

File : /PEM ON.JPG
Uploaded by : bill@... <glr7bd4o2nlwpiwtgpu3qfutd2dy3ixjw3h5zbnu@...>
Description :

You can access this file at the URL:
https://groups.yahoo.com/neo/groups/ap-gto/files/PEM%20ON.JPG

To learn more about file sharing for your group, please visit:
https://help.yahoo.com/kb/index?page=content&y=PROD_GRPS&locale=en_US&id=SLN15398

Regards,

bill@... <glr7bd4o2nlwpiwtgpu3qfutd2dy3ixjw3h5zbnu@...>


Re: AP1100 Bad Stars Issues

Bill Long
 

Well, where PEMPro wanted me to point, and stay in the green per the PEMPro Wizard was blocked by a tree, so I had to slew a bit further west to get clear skies. Perhaps that has something to do with the drift?




From: ap-gto@... on behalf of chris1011@... [ap-gto]
Sent: Saturday, February 24, 2018 2:35 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The curves you posted line up because PEMPro has lined them up for you when you clicked on the X and Y alignment tabs. You had mentioned in the PEMpro postings that they did not line up and Ray pointed out that you had drift. That drift is an indication that your polar alignment is not correct, it shows RA drift. When you have RA drift, you cannot expect round stars regardless of mount PE.


I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.
Why bother, you already have less than 1 arc sec performance. What do you expect to achieve with yet another PEMPro run? Your tracking with PEM on is essentially perfect. If you do a simple analysis of the PEM on data that you posted, you will probably find that the periodic error is on the order of 1/2 arc second. You will not exceed that and can only get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the resultant PE curve?

Roland Christen


-----Original Message-----
From: Bill Long bill@... [ap-gto]
To: ap-gto
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is what they looked like:


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool and ran it through 3 complete cycles to confirm its suggested alignment. Ray suggested I check that alignment with PEMPro the next time I am out. I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.




From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
What is the PEC curve with PEM turned ON? That is what you will be using during tracking.

When you took your PE data, you said that the individual curves did not lie on top of each other, rather they moved up with each new worm cycle. That should tell you immediately that your polar alignment is not good, and you have excessive RA drift. When your polar alignment is correct (Altitude axis properly aligned), you will basically have zero RA drift and each curve will lie on top of the next, or very close to it. Then with PEM turned on, you should be able to get no tracking error for several worm cycles when you are anywhere near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have round stars even when the mount is tracking to 1 arc sec levels with PEM on. RA drift is independent of periodic error and has nothing to do with mount tracking at sidereal rate. A perfect mount with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues







From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
Maybe I'm missing something, but I see only the raw data, not the PEC curve. Can you point it out?

Rolando



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



That is all located here:






From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.
You posted two raw PEMPro runs, but no analysis of the actual PE value. Your estimate of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the actual PE as analyzed by PEMPro so that people who read these posts do not get the false impression that we ship mounts that are out of spec. The value that defines the mount's PE is created when you press the tab "Create a PEC Curve". You will see in the upper right the value of the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect that my results will be better. Thanks for the info about expectations for non-guided exposures. 


From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.
First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro analysis of Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw data also contains errors caused by atmospheric seeing. These can easily add 3 arc sec or more to your raw data. PEMPro analysis removes these non-periodic errors caused by seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The 15 sec images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none of which are mount related. In other words, even if the mount tracked perfectly, I would not expect round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one of the popular guiding programs (MaximDL or PHD). You can use these programs to determine the base level of atmospheric seeing errors and the resultant guided performance in arc sec RMS. During guiding, when the RMS values of RA and Dec are close to equal, you will have round stars on your images.

Rolando


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues



Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have provided details to George on this problem, but I wanted to get some thoughts from the folks here on this forum as well, in the event someone has experienced a similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different cameras. 
Out of round Stars in 60 second, 120 second, and 300 second guided exposures on one camera. 

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent. I get up to 10" P-P of RA error. The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener
Takahashi FSQ106ED Native w/ no reducer
Takahashi TOA130 w/ 0.7x Tak Reducer 
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox
ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have performed testing with a wheel and OAG attached, as well as without any wheel or OAG attached, and spacers in place of them to ensure accurate chip placement. Using CCDWare CCD Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I enabled guiding and set the RA settings very, very aggressively and while the problem did not completely cure itself, the roundness of the stars improved dramatically, and tilt was reported to be reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to have very similar results on two different cameras is suspicious, and if there is a way to rule out the one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I image. The axis are separated and reassembled when the mount goes outside, and when it comes back inside each night.  In case this information is useful.

Thanks for reading.













Re: AP1100 Bad Stars Issues

Roland Christen
 

The curves you posted line up because PEMPro has lined them up for you when you clicked on the X and Y alignment tabs. You had mentioned in the PEMpro postings that they did not line up and Ray pointed out that you had drift. That drift is an indication that your polar alignment is not correct, it shows RA drift. When you have RA drift, you cannot expect round stars regardless of mount PE.

I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.
Why bother, you already have less than 1 arc sec performance. What do you expect to achieve with yet another PEMPro run? Your tracking with PEM on is essentially perfect. If you do a simple analysis of the PEM on data that you posted, you will probably find that the periodic error is on the order of 1/2 arc second. You will not exceed that and can only get the same or worse.

Ray, can you do a quick analysis of that PEM-on run and post the resultant PE curve?

Roland Christen


-----Original Message-----
From: Bill Long bill@... [ap-gto]
To: ap-gto
Sent: Sat, Feb 24, 2018 3:17 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



The PEM ON test needs to be run still, next clear night I plan to do that.

When I took my PE data, the curves seem to line up well. Here is what they looked like:


Do those look egregious to you?

As far as Polar Alignment is concerned, I used the Polemaster tool and ran it through 3 complete cycles to confirm its suggested alignment. Ray suggested I check that alignment with PEMPro the next time I am out. I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.




From: ap-gto@... <ap-gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
What is the PEC curve with PEM turned ON? That is what you will be using during tracking.

When you took your PE data, you said that the individual curves did not lie on top of each other, rather they moved up with each new worm cycle. That should tell you immediately that your polar alignment is not good, and you have excessive RA drift. When your polar alignment is correct (Altitude axis properly aligned), you will basically have zero RA drift and each curve will lie on top of the next, or very close to it. Then with PEM turned on, you should be able to get no tracking error for several worm cycles when you are anywhere near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have round stars even when the mount is tracking to 1 arc sec levels with PEM on. RA drift is independent of periodic error and has nothing to do with mount tracking at sidereal rate. A perfect mount with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto] <ap-gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues







From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
Maybe I'm missing something, but I see only the raw data, not the PEC curve. Can you point it out?

Rolando



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



That is all located here:






From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.
You posted two raw PEMPro runs, but no analysis of the actual PE value. Your estimate of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the actual PE as analyzed by PEMPro so that people who read these posts do not get the false impression that we ship mounts that are out of spec. The value that defines the mount's PE is created when you press the tab "Create a PEC Curve". You will see in the upper right the value of the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect that my results will be better. Thanks for the info about expectations for non-guided exposures. 


From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.
First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro analysis of Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw data also contains errors caused by atmospheric seeing. These can easily add 3 arc sec or more to your raw data. PEMPro analysis removes these non-periodic errors caused by seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The 15 sec images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none of which are mount related. In other words, even if the mount tracked perfectly, I would not expect round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one of the popular guiding programs (MaximDL or PHD). You can use these programs to determine the base level of atmospheric seeing errors and the resultant guided performance in arc sec RMS. During guiding, when the RMS values of RA and Dec are close to equal, you will have round stars on your images.

Rolando


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues



Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have provided details to George on this problem, but I wanted to get some thoughts from the folks here on this forum as well, in the event someone has experienced a similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different cameras. 
Out of round Stars in 60 second, 120 second, and 300 second guided exposures on one camera. 

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent. I get up to 10" P-P of RA error. The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener
Takahashi FSQ106ED Native w/ no reducer
Takahashi TOA130 w/ 0.7x Tak Reducer 
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox
ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have performed testing with a wheel and OAG attached, as well as without any wheel or OAG attached, and spacers in place of them to ensure accurate chip placement. Using CCDWare CCD Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I enabled guiding and set the RA settings very, very aggressively and while the problem did not completely cure itself, the roundness of the stars improved dramatically, and tilt was reported to be reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to have very similar results on two different cameras is suspicious, and if there is a way to rule out the one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I image. The axis are separated and reassembled when the mount goes outside, and when it comes back inside each night.  In case this information is useful.

Thanks for reading.













Re: Shutdown APCC

Stephane Charbonnel
 

Ray,

Thank you for your reply.
It's perfect for auto shutdown.
And if I have more opened my eyes, maybe I could see "Ask if OK to Exit". Sorry.

Regards
Stephane

2018-02-24 20:07 GMT+01:00 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...>:

 

Hi Stephane,

> But I would like to know if it exists a command to stop APCC as I click on the shutdown
> cross at the upper right ? (Not a kill with taskkill but a normal shutdown with message of
> waiting APCC is shutdown).

I'm not sure if this is what you are asking, but in APCC's Advanced Settings there is an "Auto Shutdown" option which automatically close APCC after the AP V2 driver disconnects. For this to work all of the applications using the AP V2 driver must explicitly disconnect from the driver first.

> An other question : I don't remember how avoid the message of shutdown APCC (OK /
> Cancel) via the menu File / Exit. Please, could you remember the procedure to avoid this
> message ?

Uncheck "Ask if OK to Exit" in Program Operation.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma



> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, February 24, 2018 10:58 AM
> To: ap-gto@...
> Subject: [ap-gto] Shutdown APCC
>
>
>
> Hello,
>
>
> When I run my automatic observatory, at one moment, I power my AP-mount and then, I
> run the .exe of APCC. All is automatic, driverV2 is automatically running so after, I connect
> my mount via my planetarium software (http://www.hyperion-astronomy.com/).
>
> But I would like to know if it exists a command to stop APCC as I click on the shutdown
> cross at the upper right ? (Not a kill with taskkill but a normal shutdown with message of
> waiting APCC is shutdown).
>
> An other question : I don't remember how avoid the message of shutdown APCC (OK /
> Cancel) via the menu File / Exit. Please, could you remember the procedure to avoid this
> message ?
>
>
> Regards
>
> Stephane Charbonnel
>
>
>
>



Re: AP1100 Bad Stars Issues

Bill Long
 

The PEM ON test needs to be run still, next clear night I plan to do that.


When I took my PE data, the curves seem to line up well. Here is what they looked like:


https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG


Do those look egregious to you?


As far as Polar Alignment is concerned, I used the Polemaster tool and ran it through 3 complete cycles to confirm its suggested alignment. Ray suggested I check that alignment with PEMPro the next time I am out. I will spend the 30 mins or so to get some fresh PEMPro PE data as well to see if there is any difference.





From: ap-gto@... on behalf of chris1011@... [ap-gto]
Sent: Saturday, February 24, 2018 12:34 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

What is the PEC curve with PEM turned ON? That is what you will be using during tracking.

When you took your PE data, you said that the individual curves did not lie on top of each other, rather they moved up with each new worm cycle. That should tell you immediately that your polar alignment is not good, and you have excessive RA drift. When your polar alignment is correct (Altitude axis properly aligned), you will basically have zero RA drift and each curve will lie on top of the next, or very close to it. Then with PEM turned on, you should be able to get no tracking error for several worm cycles when you are anywhere near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have round stars even when the mount is tracking to 1 arc sec levels with PEM on. RA drift is independent of periodic error and has nothing to do with mount tracking at sidereal rate. A perfect mount with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen




-----Original Message-----
From: Bill Long bill@... [ap-gto]
To: ap-gto
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues







From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
Maybe I'm missing something, but I see only the raw data, not the PEC curve. Can you point it out?

Rolando



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



That is all located here:






From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.
You posted two raw PEMPro runs, but no analysis of the actual PE value. Your estimate of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the actual PE as analyzed by PEMPro so that people who read these posts do not get the false impression that we ship mounts that are out of spec. The value that defines the mount's PE is created when you press the tab "Create a PEC Curve". You will see in the upper right the value of the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect that my results will be better. Thanks for the info about expectations for non-guided exposures. 


From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.
First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro analysis of Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw data also contains errors caused by atmospheric seeing. These can easily add 3 arc sec or more to your raw data. PEMPro analysis removes these non-periodic errors caused by seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The 15 sec images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none of which are mount related. In other words, even if the mount tracked perfectly, I would not expect round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one of the popular guiding programs (MaximDL or PHD). You can use these programs to determine the base level of atmospheric seeing errors and the resultant guided performance in arc sec RMS. During guiding, when the RMS values of RA and Dec are close to equal, you will have round stars on your images.

Rolando


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues



Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have provided details to George on this problem, but I wanted to get some thoughts from the folks here on this forum as well, in the event someone has experienced a similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different cameras. 
Out of round Stars in 60 second, 120 second, and 300 second guided exposures on one camera. 

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent. I get up to 10" P-P of RA error. The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener
Takahashi FSQ106ED Native w/ no reducer
Takahashi TOA130 w/ 0.7x Tak Reducer 
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox
ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have performed testing with a wheel and OAG attached, as well as without any wheel or OAG attached, and spacers in place of them to ensure accurate chip placement. Using CCDWare CCD Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I enabled guiding and set the RA settings very, very aggressively and while the problem did not completely cure itself, the roundness of the stars improved dramatically, and tilt was reported to be reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to have very similar results on two different cameras is suspicious, and if there is a way to rule out the one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I image. The axis are separated and reassembled when the mount goes outside, and when it comes back inside each night.  In case this information is useful.

Thanks for reading.











New file uploaded to ap-gto

ap-gto@...
 

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the ap-gto
group.

File : /PEMPro Error.JPG
Uploaded by : bill@... <glr7bd4o2nlwpiwtgpu3qfutd2dy3ixjw3h5zbnu@...>
Description :

You can access this file at the URL:
https://groups.yahoo.com/neo/groups/ap-gto/files/PEMPro%20Error.JPG

To learn more about file sharing for your group, please visit:
https://help.yahoo.com/kb/index?page=content&y=PROD_GRPS&locale=en_US&id=SLN15398

Regards,

bill@... <glr7bd4o2nlwpiwtgpu3qfutd2dy3ixjw3h5zbnu@...>


Re: AP1100 Bad Stars Issues

Roland Christen
 

What is the PEC curve with PEM turned ON? That is what you will be using during tracking.

When you took your PE data, you said that the individual curves did not lie on top of each other, rather they moved up with each new worm cycle. That should tell you immediately that your polar alignment is not good, and you have excessive RA drift. When your polar alignment is correct (Altitude axis properly aligned), you will basically have zero RA drift and each curve will lie on top of the next, or very close to it. Then with PEM turned on, you should be able to get no tracking error for several worm cycles when you are anywhere near the meridian.

When you have RA drift, or Dec drift for that matter, you will never have round stars even when the mount is tracking to 1 arc sec levels with PEM on. RA drift is independent of periodic error and has nothing to do with mount tracking at sidereal rate. A perfect mount with zero PE will have egg shaped stars if you have drift in either axis.

Roland Christen



-----Original Message-----
From: Bill Long bill@... [ap-gto]
To: ap-gto
Sent: Sat, Feb 24, 2018 2:16 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues







From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 12:07 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 
Maybe I'm missing something, but I see only the raw data, not the PEC curve. Can you point it out?

Rolando



-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 2:04 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



That is all located here:






From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 11:59 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.
You posted two raw PEMPro runs, but no analysis of the actual PE value. Your estimate of 9 to 10 arc sec P-P is not backed by actual analysis. Please post the actual PE as analyzed by PEMPro so that people who read these posts do not get the false impression that we ship mounts that are out of spec. The value that defines the mount's PE is created when you press the tab "Create a PEC Curve". You will see in the upper right the value of the mount's periodic error in +- arc seconds.

Roland Christen
Astro-Physics Inc.


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:52 pm
Subject: Re: [ap-gto] AP1100 Bad Stars Issues



I sent another mail correcting my original statement. I had some more coffee, then read it again. Ray had a look at the curve via the PEMPro forums and I think we are good to go on that front.

I will test this again, with PEMPro enabled and guiding running. I suspect that my results will be better. Thanks for the info about expectations for non-guided exposures. 


From: ap-gto@... gto@...> on behalf of chris1011@... [ap-gto] gto@...>
Sent: Saturday, February 24, 2018 10:44 AM
To: ap-gto@...
Subject: Re: [ap-gto] AP1100 Bad Stars Issues
 
 

The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.
First of all, 9" P-P is only 28% larger than +- 3.5". The error of 9" P-P is equal to +- 4.5 ".

I believe you misunderstand what periodic error is and how it is measured and specified.
A screen capture of the PEMPro run would be helpful, along with the PEMPro analysis of Periodic error. Remember, when you are doing a PEMPro run on the sky, the raw data also contains errors caused by atmospheric seeing. These can easily add 3 arc sec or more to your raw data. PEMPro analysis removes these non-periodic errors caused by seeing, drift, etc and provides the true mount tracking performance.

I saw your images that you sent and they looked normal to me and George. The 15 sec images had perfectly round stars, consistent with typical winter seeing.

I would never expect unguided images to be round for a number of reasons, none of which are mount related. In other words, even if the mount tracked perfectly, I would not expect round star images in an unguided exposure of any normal length.

A better indication of performance is the RMS value of your guiding, using one of the popular guiding programs (MaximDL or PHD). You can use these programs to determine the base level of atmospheric seeing errors and the resultant guided performance in arc sec RMS. During guiding, when the RMS values of RA and Dec are close to equal, you will have round stars on your images.

Rolando


-----Original Message-----
From: Bill Long bill@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Sat, Feb 24, 2018 12:07 pm
Subject: [ap-gto] AP1100 Bad Stars Issues



Hello all,

I have contacted A-P about some recent imaging challenges I have had, and have provided details to George on this problem, but I wanted to get some thoughts from the folks here on this forum as well, in the event someone has experienced a similar problem.

Problem Statement:
Out of round stars in 15 and 30 second unguided exposures, on two different cameras. 
Out of round Stars in 60 second, 120 second, and 300 second guided exposures on one camera. 

Possible Red Herring or Evidence for Concern:
I have run PEMPro and the readings of periodic error are wildly inconsistent. I get up to 10" P-P of RA error. The last one I ran was close to 9" P-P.  This is almost 3 times the published specification of +/- 3.5" without any error correction.

Polar Alignment Method:
Polemaster, 3 complete cycles per alignment, repeatable results.

Gear:
Stellarvue 80mm Refractor w/ SV80 Field Flattener
Takahashi FSQ106ED Native w/ no reducer
Takahashi TOA130 w/ 0.7x Tak Reducer 
AP1100 GTO CP4 w/ Auto-Adjusting Gearbox
ASI 183MM Pro CMOS Camera
ASI 294MC Pro CMOS Camera

Software:
APCC Pro
ASCOM v2 AP Driver
Sequence Generator Pro

All cameras tested were properly spaced on each respective scope. I have performed testing with a wheel and OAG attached, as well as without any wheel or OAG attached, and spacers in place of them to ensure accurate chip placement. Using CCDWare CCD Inspector 2, both cameras are reported to be showing 20% tilt. As a test, I enabled guiding and set the RA settings very, very aggressively and while the problem did not completely cure itself, the roundness of the stars improved dramatically, and tilt was reported to be reduced to 2%.

The cameras could be involved in the problem, I am not ruling that out, but to have very similar results on two different cameras is suspicious, and if there is a way to rule out the one constant in all of this testing (the mount) I would like to do that.

The mount is not permanently mounted. I set up and tear down each night I image. The axis are separated and reassembled when the mount goes outside, and when it comes back inside each night.  In case this information is useful.

Thanks for reading.