First light with Mach1 - a query


Paul
 

Got my new Mach1 on Monday, and been playing around this week with it indoors. Just got out tonight under the stars - briefly before the clouds came in!

I've put a screenshot of my first guiding session in the Files section (PHD2Screenshot.PNG). I'm happy with that! Especially considering the target (Corona Australis) was only at 45 degrees altitude at the time, and that was out of the box with the same settings I last used with my EQ6 that it's just replaced. Thanks AP! 

However, I had one issue I'm looking for ideas on. My sequence of operations was, as far as I can recall, 
- Set up mount in Park 3 position and unparked (and switched off tracking)
- Started Sharpcap polar alignment
- Slewed mount west about 90 degrees using the buttons in APCC at a slew speed of 600x
- Completed Sharpcap PA (by the way, those adjustment bolts are super smooth and I can make adjustments in one axis with no effect on the other. Nice!! Got to under 1' PA error in about 2 minutes of adjustment!!)
- Initiated a park to Park 3
- Unparked (now tracking)
- Slewed to target using SGP (connected to APv2 driver to APCC)
- Plate solved (using SGP's "centre target").

At this point it took ages to plate solve, and when it finally did it was about 6 degrees out and the RCAL was rejected as being too far out.

When I parked back to Park3, I noticed the RA axis was way off on the registration marks. Loosening the clutches and putting the marks back in line manually, I was able to do the above SGP slew and solve without a problem.

What could I have done in the above sequence to get the RA out of sync? Was it that manual slew using APCC somehow. I don't think the clutches were loose enough for it to slip (though I could be wrong I guess).

Sorry for the long rambling message. Any ideas appreciated.

Another question would be how do I stop APCC rejecting an RCAL that it thinks is too far out - in this case, that would've been enough to solve my problem without having to manually re-park the mount.

But apart from the query, a nice first night with the mount! 

Thanks,
Paul


Roland Christen
 

When you first set the mount up in Park3, it was not polar aligned and was probably off by some degrees. Going to your first object would have been in error - which in this case was 6 degrees off. When you polar aligned the mount you also changed the initial mechanical alignment of Park3 so changing the polar alignment invalidates the exact position of the original Park positions. In other words, for these park positions to be accurate requires the polar alignment to be correct first. Personally i don't worry about the accuracy of going to park until the mount is polar aligned and initialized (calibrated) on a known star.

Rolando



-----Original Message-----
From: privatekey42@... [ap-gto]
To: ap-gto
Sent: Fri, Aug 3, 2018 10:40 am
Subject: [ap-gto] First light with Mach1 - a query



Got my new Mach1 on Monday, and been playing around this week with it indoors. Just got out tonight under the stars - briefly before the clouds came in!

I've put a screenshot of my first guiding session in the Files section (PHD2Screenshot.PNG). I'm happy with that! Especially considering the target (Corona Australis) was only at 45 degrees altitude at the time, and that was out of the box with the same settings I last used with my EQ6 that it's just replaced. Thanks AP! 

However, I had one issue I'm looking for ideas on. My sequence of operations was, as far as I can recall, 
- Set up mount in Park 3 position and unparked (and switched off tracking)
- Started Sharpcap polar alignment
- Slewed mount west about 90 degrees using the buttons in APCC at a slew speed of 600x
- Completed Sharpcap PA (by the way, those adjustment bolts are super smooth and I can make adjustments in one axis with no effect on the other. Nice!! Got to under 1' PA error in about 2 minutes of adjustment!!)
- Initiated a park to Park 3
- Unparked (now tracking)
- Slewed to target using SGP (connected to APv2 driver to APCC)
- Plate solved (using SGP's "centre target").

At this point it took ages to plate solve, and when it finally did it was about 6 degrees out and the RCAL was rejected as being too far out.

When I parked back to Park3, I noticed the RA axis was way off on the registration marks. Loosening the clutches and putting the marks back in line manually, I was able to do the above SGP slew and solve without a problem.

What could I have done in the above sequence to get the RA out of sync? Was it that manual slew using APCC somehow. I don't think th e clutches were loose enough for it to slip (though I could be wrong I guess).

Sorry for the long rambling message. Any ideas appreciated.

Another question would be how do I stop APCC rejecting an RCAL that it thinks is too far out - in this case, that would've been enough to solve my problem without having to manually re-park the mount.

But apart from the query, a nice first night with the mount! 

Thanks,
Paul



Paul
 

Thanks Rolando. I'm not sure that was the issue. My PA was only 0.5 degree out at most, and in any case I didn't do any slew in that sequence until the PA was spot on.

I guess I must've done something dumb. But not sure what. I'll see what happens next time. What I think was that when I went back to Park 3 after the PA it wasn't in Park 3 position, and that caused the issue with it being out after the slew. But not sure why that would've happened. 

That aside, as I said, the PA process was great with such smooth and precise adjustment knobs - compared to my old EQ6. It's a beautiful piece of engineering! 

Regards,
Paul


Paul
 

I guess one side question out of my long-winded one that I'd be keen to see if there's an answer to is is there a way to force the driver (or APCC or whatever)  to accept an RCAL it thinks is too far out. 

If in future I get into a weird situation where the mount is thinking its pointing somewhere its not, but the PA is correct, and I trust the plate solve in SGP to do its thing (which I do), then I simply want it to accept what SGP says without giving an error.

So just a temporary removal of the threshold (how?) or changing that RCAL to SYNC again (how?). What's the best way using my SGP + AP driver (or APCC) combo?

Thanks,
Paul


Ray Gralak
 

Hi Paul,

I guess one side question out of my long-winded
one that I'd be keen to see if there's an answer
to is is there a way to force the driver (or APCC
or whatever) to accept an RCAL it thinks is
too far out.
In APCC's Advanced Settings dialog there is an option called "Prevent Errant RECALs". Disabling that option will eliminate the 5 degree limit. However, I recommend that you enable the option again afterwards to prevent any potentially bad plate solves from recalibrating the mount to the wrong position.

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 V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, August 4, 2018 3:27 PM
To: ap-gto@...
Subject: [ap-gto] Re: First light with Mach1 - a query



I guess one side question out of my long-winded one that I'd be keen to see if there's an answer to is is there a
way to force the driver (or APCC or whatever) to accept an RCAL it thinks is too far out.

If in future I get into a weird situation where the mount is thinking its pointing somewhere its not, but the PA is
correct, and I trust the plate solve in SGP to do its thing (which I do), then I simply want it to accept what SGP says
without giving an error.

So just a temporary removal of the threshold (how?) or changing that RCAL to SYNC again (how?). What's the
best way using my SGP + AP driver (or APCC) combo?

Thanks,
Paul


Bill Long
 

In my experience, that error usually indicates that something has gone awry. 




From: ap-gto@... on behalf of 'Ray Gralak (Groups)' groups3@... [ap-gto]
Sent: Saturday, August 4, 2018 3:45 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: First light with Mach1 - a query
 
 

Hi Paul,

> I guess one side question out of my long-winded
> one that I'd be keen to see if there's an answer
> to is is there a way to force the driver (or APCC
> or whatever) to accept an RCAL it thinks is
>too far out.

In APCC's Advanced Settings dialog there is an option called "Prevent Errant RECALs". Disabling that option will eliminate the 5 degree limit. However, I recommend that you enable the option again afterwards to prevent any potentially bad plate solves from recalibrating the mount to the wrong position.

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 V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, August 4, 2018 3:27 PM
> To: ap-gto@...
> Subject: [ap-gto] Re: First light with Mach1 - a query
>
>
>
> I guess one side question out of my long-winded one that I'd be keen to see if there's an answer to is is there a
> way to force the driver (or APCC or whatever) to accept an RCAL it thinks is too far out.
>
> If in future I get into a weird situation where the mount is thinking its pointing somewhere its not, but the PA is
> correct, and I trust the plate solve in SGP to do its thing (which I do), then I simply want it to accept what SGP says
> without giving an error.
>
> So just a temporary removal of the threshold (how?) or changing that RCAL to SYNC again (how?). What's the
> best way using my SGP + AP driver (or APCC) combo?
>
> Thanks,
> Paul
>
>


Paul
 

Thanks Ray.


Paul
 

Sure. I was just after a way to quickly fix it without having to reset everything.


Ron Kramer
 

Paul, try a blind/sync in SGP first.  (well polar align first) then move off the pole a ways and do a blind/sync.  This is usually much faster than the local plate solve search. This will sync the mount properly and then a plate solve using your local database will then be much faster.  From then on you can just do SGP - slew and center using platesolve2.  works GREAT for me, but after I mess with clutches or release the worm for balance - I then need to do another blind/sync to get back to normal.  Then plate solves and centering in SGP is pretty quick and extremely accurate. My targets always appear dead center.  Latley I've been getting .3x rms average with a 6" refractor and a 80mm refractor side by side.  I sometimes see .25 and sometimes .45 but 90% of the time I'm in the 0.3x range.  I love my Mach1 too.



On Sat, Aug 4, 2018 at 7:05 PM privatekey42@... [ap-gto] <ap-gto@...> wrote:
 

Sure. I was just after a way to quickly fix it without having to reset everything.


Eric Dreher
 

I use a similar procedure with my Mach1. Two nights ago seeing was pretty good with RMS at 0.31” and dips into the high 0.2x” range.

I experimented a bit with PEM on and off, with a difference so slight it almost wasn’t worth the bother. My native PE without correction is 3.15” pk-pk. Just a fantastic mount.


Paul
 

Thanks guys. Your guiding seems better than mine but early days yet😊


Ron Kramer
 

It took me some months to achieve what I'm getting now.  Last night - It was a bit poorer, I was seeing smaller stars look like horizontal lines. After 9 subs and much wondering - why I'd see a horizonal elongation, it HIT ME...  I forgot to turn off the dome fan. (fan used to keep condensation from forming on the mount/scope) once I turned it off I went from .55 to .35 simply due to no fan blowing on the scope.  Goes to show - how little 1 micron is. = )


On Sun, Aug 5, 2018 at 12:33 AM privatekey42@... [ap-gto] <ap-gto@...> wrote:
 

Thanks guys. Your guiding seems better than mine but early days yet😊


Roland Christen
 

Had the same thing happen at our remote observatory in Chile. The fans on the back of the CCD camera were not low vibration type and the stars were fairly large ovals even in a 1 sec exposure. As soon as we turned the fans off, the stars went perfectly round. We ended up replacing the fans with low vibe ones and problem solved.

Rolando



-----Original Message-----
From: Ron Kramer ronkramer1957@... [ap-gto]
To: ap-gto
Sent: Thu, Aug 9, 2018 3:08 pm
Subject: Re: [ap-gto] Re: First light with Mach1 - a query



It took me some months to achieve what I'm getting now.  Last night - It was a bit poorer, I was seeing smaller stars look like horizontal lines.. After 9 subs and much wondering - why I'd see a horizonal elongation, it HIT ME...  I forgot to turn off the dome fan. (fan used to keep condensation from forming on the mount/scope) once I turned it off I went from .55 to .35 simply due to no fan blowing on the scope.  Goes to show - how little 1 micron is. = )


On Sun, Aug 5, 2018 at 12:33 AM privatekey42@... [ap-gto] <ap-gto@...> wrote:
 
Thanks guys. Your guiding seems better than mine but early days yet😊



Ben Koltenbah
 

I had this very same issue recently.  I finally replaced the CCD fan with a low vibration maglev one (suggested by George at AP), and that turned my stars round again.  Prior to that the fan vibrated so much that it built up a resonance with my camera and ONAG combination.  The stars were little oval doughnuts!

Ben