Date   

Re: Things that customers do that drive me nuts on CN

Bill Long
 

Good to hear.


Throughout this, it sounded like you were equating low MinMo values to better images. Not sure if you were actually intending to do that, but its most certainly not the case. Getting the correct guiding parameters set should allow you to get the best images your seeing will allow for. 




From: ap-gto@... on behalf of stephenjwinston@... [ap-gto]
Sent: Tuesday, July 10, 2018 1:14 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: Things that customers do that drive me nuts on CN
 
 

An update from last night's imaging run - and it's good news :)


I gathered some more data on NGC7000, including doing an automated meridian flip using SGP.  The guide settings matched a lot of what has been recommended here: 2s exposures and MinMove of 0.40 on DEC.  The results look pretty good :)

One caveat being that imaging NGC7000 is basically straight up from my location when it crosses the meridian, and that has been my least problematic orientation for the mount.  I'll be repeating those guide settings tonight on M16 or M8 to see if it also has the same positive result.

Steve


Re: Things that customers do that drive me nuts on CN

Stephen Winston
 

An update from last night's imaging run - and it's good news :)

I gathered some more data on NGC7000, including doing an automated meridian flip using SGP.  The guide settings matched a lot of what has been recommended here: 2s exposures and MinMove of 0.40 on DEC.  The results look pretty good :)

One caveat being that imaging NGC7000 is basically straight up from my location when it crosses the meridian, and that has been my least problematic orientation for the mount.  I'll be repeating those guide settings tonight on M16 or M8 to see if it also has the same positive result.

Steve


Re: Things that customers do that drive me nuts on CN

Ron Kramer
 

If this group was easier to use, easier to read, didn't repeat everything over and over and over and over... included attachments.  People wouldn't need places like cloudynights.
Forums are VERY EASY to install in your website. Most are free.  Very easy to install. I believe nexdome (who are not web savvy) just installed one from wordpress. 
With AP's reputation of being the best of the best in everything they do, I'm surprised you settle for this yahoo group crap.



On Tue, Jul 10, 2018 at 12:50 PM stephenjwinston@... [ap-gto] <ap-gto@...> wrote:
 

Thanks Ray - really looking forward to your interpretation of the logs.  


Let me know if you need any additional data - I still have the ascom logs from my previous nights testing / older PHD2 logs.  I didn't include them in the zip as they are not relevant to the PHD log I gave you.

And at the risk of beating a dead horse :), I think the problem breaks down into two parts:

1 : What triggers the DEC excursion in the first place. 
Based on all the great info from Roland & Co, this can likely be eliminated by using more reasonable MinMove settings.

2 : Why the excursion spikes and then takes so long to be corrected (usually 15-30 seconds)
My interpretation of the graph (several corrective pulses over multiple seconds with no response, followed by a sudden swing and over correction) is that it looks like stiction.  As the full swing happens over such a long time period (30+ seconds), I don't think it can be described as a "fast" oscillation.  But I could be wrong - maybe I just need to re-calibrate my definition of fast :).

My concern is that I may be able to avoid this issue with less aggressive MinMove settings using my current short-focal length / large imaging scale set-up (which is pretty forgiving).  But when I switch to a more demanding / longer focal length set-up the issue may return.

So, I'd really like to understand both parts of the problem - the initial trigger and the mounts (lack of) response to corrective pulses.

Steve



Re: Mach 1 Software

C. E. Steuart Dewar <cesdewar@...>
 

I installed a Rayox saddle on my mount and yes, it works beautifully and I find it a huge improvement in confidently mounting my C-11 Edge. Previously, especially in the dark, I was always concerned that I had the rail properly grabbed by the mount. It’s expensive, yes, but dropping a scope is a lot more expensive ;)



Regards,

CESDewar



From: ap-gto@yahoogroups.com <ap-gto@yahoogroups.com>
Sent: Thursday, July 5, 2018 3:18 PM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] Mach 1 Software





Hi All,



I will be receiving my mount soon but will be waiting on my OTA for a few months (FSQ106). So I am piecing together all the parts that I will be needing in the mean time. I would like to tap the people experienced with using the mounts to make sure I am efficient in my spending and am set up for minimal problems:



1. I am planning on a Rayox saddle. Just making sure it works well with the mount?



2. The software part is where I get a tad confused. George was super helpful explaining the ASCOM requirement for the mount and some of the other items. But where I got a little lost was needing a separate software for the camera (MaximDL?) and something to guide through the computer like SkyX. Any input on warts those might have or if there is something else recommended as well as any other software. I already have PS and am pretty good with using it for my bird photography. Also, what would 'synch' them all up so they work together?





3. I am getting the camera a little later after I get everything else set up. So I can get the fittings correct and the focuser & filer wheel later in the year.. I know the sensors I would prefer so I have narrowed the camera down quite a bit.



Thanks for helping out a noob.



Jon Swanson









[Non-text portions of this message have been removed]


Re: Things that customers do that drive me nuts on CN

Stephen Winston
 

Thanks Ray - really looking forward to your interpretation of the logs.  

Let me know if you need any additional data - I still have the ascom logs from my previous nights testing / older PHD2 logs.  I didn't include them in the zip as they are not relevant to the PHD log I gave you.

And at the risk of beating a dead horse :), I think the problem breaks down into two parts:

1 : What triggers the DEC excursion in the first place. 
Based on all the great info from Roland & Co, this can likely be eliminated by using more reasonable MinMove settings.

2 : Why the excursion spikes and then takes so long to be corrected (usually 15-30 seconds)
My interpretation of the graph (several corrective pulses over multiple seconds with no response, followed by a sudden swing and over correction) is that it looks like stiction.  As the full swing happens over such a long time period (30+ seconds), I don't think it can be described as a "fast" oscillation.  But I could be wrong - maybe I just need to re-calibrate my definition of fast :).

My concern is that I may be able to avoid this issue with less aggressive MinMove settings using my current short-focal length / large imaging scale set-up (which is pretty forgiving).  But when I switch to a more demanding / longer focal length set-up the issue may return.

So, I'd really like to understand both parts of the problem - the initial trigger and the mounts (lack of) response to corrective pulses.

Steve



APPM --- strange point values in a model

Dmitri
 

Hello,

I ran APPM for the first time.  Over all there were 47 points and all were plate solved just fine.
The differences between assumed RA,DEC and what plate solving showed were in  [-15,15] arc-min for all but one point. Which showed the differences -5263 arc-min in RA and 2706 arc-min in DEC.
Looking at pairs coordinates they should be about 1 arc-min and 6 arc-min (below is part of APPM log corresponding to this point).  Such big reported differences look like an error.  I am wondering if this point will adversely affect the pointing model.

Should I just remove the point from the model?
Is this a bug in APPM that affects modeling or it affects only visual presentation of mapped points?


==========================================================================
0000972 2018-07-09 23:03:56.922:       Info,        SlewNext, Starting Slew to Point 22
0000973 2018-07-09 23:03:56.927:       Info,       Slew Next, East=False, Dec=45, HA=1.5084944665313, MerDelay=0.25, MerOffset=0
0000974 2018-07-09 23:03:57.020:       Info,   State Machine, Entering State=PreSlewing
0000975 2018-07-09 23:04:02.453:       Info,   State Machine, Entering State=Slewing
0000976 2018-07-09 23:04:02.706:       Info,   State Machine, Entering State=StartSettle
0000977 2018-07-09 23:04:02.745:       Info,     StartSettle, Starting Settle wait time
0000978 2018-07-09 23:04:02.955:       Info,   State Machine, Entering State=WaitSettle
0000979 2018-07-09 23:04:07.955:       Info,     StartSettle, Settling Time Complete
0000980 2018-07-09 23:04:08.206:       Info,   State Machine, Entering State=StartImage
0000981 2018-07-09 23:04:08.249:       Info,   State Machine, Starting Exposure, Duration=10, LST=17.2351916666667
0000982 2018-07-09 23:04:08.249:       Info,   State Machine, LST Mid Image=17.2367194444444
0000983 2018-07-09 23:04:08.249:       Info,  StartTakeImage, Sequence Generator Pro: Binning=1, Duration=10, IsDarkFrame=False
0000984 2018-07-09 23:04:18.455:       Info,   State Machine, Entering State=WaitImage
0000985 2018-07-09 23:04:18.532:       Info,   State Machine, Exposure Done. Saving to: C:\Users\Dmitri\Documents\Astro-Physics\APPM\Image-APPM-2018-07-09-222429.txt-0022-RA_15.724-DEC_45.000.fit
0000986 2018-07-09 23:04:22.007:       Info,   State Machine, Entering State=PlateSolveStart
0000987 2018-07-09 23:04:22.070:       Info,   State Machine, Starting Platesolve via SGPro PlateSolver: Scope RA,Dec=  15h 43m 24.9s(       15.72358),     45° 00' 00"(       45.00000)
0000988 2018-07-09 23:04:22.203:       Info,   State Machine, Entering State=PlateSolveWait
0000989 2018-07-09 23:04:33.287:       Info,   State Machine, Solved RA,Dec=        15h 42m 49.6s(       15.71378),     45° 06' 26"(       45.10722)
0000990 2018-07-09 23:04:33.287:       Info,   State Machine, Solved Image Scale X,Y=1.26891976731497, 1.26891976731497
0000991 2018-07-09 23:04:33.287:       Info,   State Machine, Iteration,Measurement,HA,RA,Dec=   0,  21, 8.2862215206667, -5263.442 arc-min, 2706.433 arc-min
0000992 2018-07-09 23:04:33.411:       Info,       ModelFile, 636B     0| 45.000000|  1.508494|0|0|  0.000000|  0.000000|1| 15.713778| 45.107217|  0.000000|  8.286222|  0001-01-01T00:00:00|  0.0|  0.0|0|       0.0|0|    0|0|    0||C:\Users\Dmitri\Documents\Astro-Physics\APPM\Image-APPM-2018-07-09-222429.txt-0022-RA_15.724-DEC_45.000.fit



Re: Things that customers do that drive me nuts on CN

Roland Christen
 


And this is where the PHD's recommendation greatly differs.  It is much more aggressive.  In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71 arc seconds.  
That peak error may be +- error or Peak to Peak. If that's the case, divide it by 2 to get the peak error. Then multiply it by 0.6  to get 1.1 arc sec or 0.37 pixels (or multiply by 0.8 to get 0.5 pixel MinMove).

Rolando


-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Tue, Jul 10, 2018 11:23 am
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN




>That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value. 

Yep.  And that is exactly what PHD2 Guiding Assistant is doing (measuring seeing with DEC guiding disabled).

>Then set the MinMove to between 60 and 80% of that value. 

And this is where the PHD's recommendation greatly differs.  It is much more aggressive.  In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71 arc seconds.  

Using your 60% rule would put my MinMove at 60% of 3.71 arc-s, or 0.75 px, instead of the 0.20 px PHD recommended.   I would say that 0.75 px is probably too pessimistic and something in the 0.30-0.40 range is probably more reasonable.

>I don't know how much more clear I can make this.
What you are saying is fully understood :).

As I previously mentioned to Bill and Wade, one of the outcomes of this will hopefully to get PHD2 to make more reasonable recommendations based on the Guiding Assistants measurements.




Re: Things that customers do that drive me nuts on CN

Stephen Winston
 


>That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value. 

Yep.  And that is exactly what PHD2 Guiding Assistant is doing (measuring seeing with DEC guiding disabled).

>Then set the MinMove to between 60 and 80% of that value. 

And this is where the PHD's recommendation greatly differs.  It is much more aggressive.  In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71 arc seconds.  

Using your 60% rule would put my MinMove at 60% of 3.71 arc-s, or 0.75 px, instead of the 0.20 px PHD recommended.   I would say that 0.75 px is probably too pessimistic and something in the 0.30-0.40 range is probably more reasonable.

>I don't know how much more clear I can make this.
What you are saying is fully understood :).

As I previously mentioned to Bill and Wade, one of the outcomes of this will hopefully to get PHD2 to make more reasonable recommendations based on the Guiding Assistants measurements.


Re: Things that customers do that drive me nuts on CN

Roland Christen
 

That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value. Then set the MinMove to between 60 and 80% of that value. If the star motion is +-2 arc seconds peak to peak, then set the Min Move to 1.6 arc sec (or 0.48 pixels for a 3 arc sec per pixel scale). I don't know how much more clear I can make this.

If you set the MinMove to less than this value, you can guarantee you will have oscillations caused by guider chasing the seeing. Remember, you are trying to re-position a mechanical gear wheel by a few nanometers even at 1.6 arc seconds.

All we're trying to do in guiding Dec is to set a boundary within which we allow the star to bobble back and forth unimpeded. If it exceeds the boundary we want to nudge it gently back towards zero. We do NOT want to set up small rapid oscillations back and forth which can get out of hand.

Rolando

-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Tue, Jul 10, 2018 10:25 am
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN




>You say that you have seen peak Dec errors of 3.71 arc seconds. Well the fact is that this error happened in the past and the next measurement may show a different position of the star,

Again, to try clarify:  The 3.71 arc seconds error is what PHD2 Guiding Assistant measured as the Peak Error while calibrating with DEC tracking disabled.

Bill had suggested that users should us the Peak Error from PHD GA to set MinMo.

I was just making the point that the GA measured Peak Error is not necessarily the right metric to set MinMo - in my case it would mean setting MinMo to 1.25 px





Re: Mach 1 Software

Ron Kramer
 

I've not gotten that deep into it. I'm still trying to work out kinks. The manual (being a translation from French is less than detailed). But the program keeps forcing me to come back and work with it again.  I run APCC in the background. I have PemPro but have not really had a chance to use it after a couple of failed attempts.   I settled for ascoms  "record PEC" and playback and I see the sine wave is gone from my guiding. I've been living with that as I've been dealing with other issues.  (Dome rotator and shutter firmware updates and working with the author on that) Finally working well. I sold a 127mm and replaced with 152mm scope and now dealing with trying to land an adapter to install a FT and EF to the new tube.  Wrong one set, new one on the way - I may be up again after months of down time next week.

Prism is freaking amazing.  But I don't have it under control yet. I've reverted back to SGP for real imaging - until I get Prism fully working.  For many it may work out of the gate, I have a... complex? setup in that I'm fully remote and Still have some kinks (some issues with dome graphic and mount graphic displaying properly with poth, which I had to add for a dome hub).  If I use a virtual com port on APCC for the dome com port (will it hub a 2nd connection?).

I then have issues with the lodestar X2 connection.  It works, but I get a interlaced image each star as 2 points. (others do not have this issue) and I don't have the interlaced image with this camera and driver in PHD2.  ???!!!

What keeps me from tossing it aside is I have 60 more days of trial and the I have working is amazing.  Once the scope is setup with focuser I can delve into focusing features and Hamzat said he'd timeview into my setup and 
check my PRism configuration.  I WANT TO USE IT.  But time will tell. 

On the other hand I love WWT for goto's.  No other program shows actual full sky surveys.  I wanted to do some test the other day and IC5070 is just below my tree line.  Using WWT I could see other areas of interest above the tree line and did some sweet image of the outer fringes that I felt were more interesting than the Pelican itself.  Only because in WWT I could see them and click on the spot and the mach1 nailed it. (as it always does). I've found no need for a pointing model. HOWEVER I am now only at 1210 fl and that may be very different for those in the 2000+ focal length area. 

Biggest problem with Prism is (few if anyone use it in the U.S.) so it's hard to get experienced help.  From what I've heard it's extremely popular in Europe. In use for over 10 years. 


On Mon, Jul 9, 2018 at 10:09 PM Bill Long bill@... [ap-gto] <ap-gto@...> wrote:
 

SkyX doesnt do meridian flips. :( LTI does, but then it doesnt do guiding. 


Thus my APPM journey!




From: ap-gto@... <ap-gto@...> on behalf of 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...>
Sent: Monday, July 9, 2018 6:57 PM
To: ap-gto@...
Subject: RE: [ap-gto] Mach 1 Software
 
 

Hi Ron,

> PRISM it does IT ALL in one program.

I am not so sure about that. TheSkyX software is probably a better example of an "all in one" astronomy program because TheSkyX doesn't even need an ASCOM driver for many mounts, unlike PRISM which I think requires ASCOM mount drivers. Besides, having a monolithic all in one program is not necessarily an advantage because you may be out of luck if a camera or other hardware component you want to buy in the future is not supported.

Also, I think there may be some misleading information in its set of features. For instance, I think that Prism Pro says "PEC" is one of its features. That's "Periodic Error Correction" to most people. However, while I think Prism can measure periodic error, can it upload a PEC curve into an AP mount like PEMPro can? I diddn't see that it could. If all it does is measure PE then I think there are probably better free software applications to analyze periodic error, like my (free) PEMPro Log Analyzer that can analyze PHD2 and PEMPro logs.

And while Prism Pro does pointing correction it doesn't seem to do tracking rate correction like APCC Pro, or TheSkyX's ProTrack.

Ron, please feel free to correct anything above that you believe is wrong.

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: Monday, July 9, 2018 8:29 AM
> To: ap-gto@...
> Subject: Re: [ap-gto] Mach 1 Software
>
>
>
> Pick up a lot of extension tubes. They're cheap and will be needed to position the camera at the proper distance to
> achieve focus. I have about 8-10 inches of them. (in various sizes).
> Each camera uses a combination of (field flattener, extension tubes... typically adding 4-6 inches of distance in
> addition to the focuser throw. I prefer my focuser more inside and not over extended
> so I use more extension tubes than I really have to. Less tubes means you need to draw the focuser out more
> which (depending on focuser) can add sag or just more stress on the focuser.
>
> Software: SGP with PHD2 and platesolve2 is most cost effective (lowest cost) or course APCC. another option is
> PRISM it does IT ALL in one program. Really is the simplest as it's all in one and configuration is in menu... steps.
> Only drawback is it's 10 years in use in Europe and not heavily used in the U.S. (yet) so getting help is much harder
> than SGP and assorted free tools. (PHD2).
>
> SADDLES: I like ADM and Losmandy stuff. I have a Losmandy plate and two saddles for a side by side dual
> setup. I'm a noob too - I started in this last May. At present I'm waiting months for a ES152mm adapter to mount a
> 3" feather touch on the scope. After a 4 month wait for the feather touch focuser to arrive. Manual focus is NOT
> FUN. Especially when you operate your scope setup from 300 ft away.. =)
>
>
>
>
>
>
>
> On Fri, Jul 6, 2018 at 4:06 AM trapman66@... [ap-gto] <ap-gto@...> wrote:
>
>
>
>
>
> Hi All,
>
>
>
>
> I will be receiving my mount soon but will be waiting on my OTA for a few months (FSQ106). So I am piecing
> together all the parts that I will be needing in the mean time. I would like to tap the people experienced with using
> the mounts to make sure I am efficient in my spending and am set up for minimal problems:
>
>
>
>
> 1. I am planning on a Rayox saddle. Just making sure it works well with the mount?
>
>
>
>
> 2. The software part is where I get a tad confused. George was super helpful explaining the ASCOM
> requirement for the mount and some of the other items. But where I got a little lost was needing a separate
> software for the camera (MaximDL?) and something to guide through the computer like SkyX. Any input on warts
> those might have or if there is something else recommended as well as any other software. I already have PS and
> am pretty good with using it for my bird photography. Also, what would 'synch' them all up so they work together?
>
>
>
>
> 3. I am getting the camera a little later after I get everything else set up. So I can get the fittings correct and
> the focuser & filer wheel later in the year. I know the sensors I would prefer so I have narrowed the camera down
> quite a bit.
>
>
>
>
> Thanks for helping out a noob.
>
>
>
>
> Jon Swanson
>
>
>
>
>
>
>
>


Re: Things that customers do that drive me nuts on CN

Stephen Winston
 


>You say that you have seen peak Dec errors of 3.71 arc seconds. Well the fact is that this error happened in the past and the next measurement may show a different position of the star,

Again, to try clarify:  The 3.71 arc seconds error is what PHD2 Guiding Assistant measured as the Peak Error while calibrating with DEC tracking disabled.

Bill had suggested that users should us the Peak Error from PHD GA to set MinMo.

I was just making the point that the GA measured Peak Error is not necessarily the right metric to set MinMo - in my case it would mean setting MinMo to 1.25 px



Re: Things that customers do that drive me nuts on CN

Roland Christen
 


The problem with using the peak value is that is is susceptible to random worst case scenarios: sudden huge spike in seeing, piece of dirt in DEC worm, moth landing on the camera :).
Again, you turn off Dec guiding and just look at the Dec axis peak motions of the star. You eliminate any guider commands and all motor and axis motions. You have only the pure atmospheric movements, the peak value which the star is bobbling around on your guider graph. Set the Min Move to between 60 and 80% of that peak value (minus any large outliers). Drop the aggressiveness down from 100% to between 60 and 80% for starters. Let the Dec axis guide slowly to remove the steady drift, not trying to follow every bobble of the guide star.

RMS and Peak are not related. You can have a 20 arc second peak excursion for a short period of time and the RMS value may be the same as five excursions of 3 arc seconds in the same time period. Look up "root mean square" and how that is calculated from peak value and time period. RMS is normally used in electrical power transmission to calculate the heating value of a particular waveform.

Rolando


-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Tue, Jul 10, 2018 10:01 am
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN



Hi Roland,

I just responded to Bill on this before seeing your post.

RMS is a measure of error from the predicted data, which in this case is the error with respect to straight line tracking, I would have thought? So isn't the RMS primarily determined by the variation ("error") caused seeing?  But maybe I'm misunderstanding how PHD2 calculates this value.

Anyway, the max DEC error I see with guiding turned off can vary greatly.  I just uploaded a screen grab from last night's GA calibration run.  The reported peak DEC error was 3.71 arc-s or 1.25 px.  I think using that as the DEC MinMo would be overly pessimistic.

The problem with using the peak value is that is is susceptible to random worst case scenarios: sudden huge spike in seeing, piece of dirt in DEC worm, moth landing on the camera :).  It doesn't necessarily give a good ide a of what the average seeing or tracking will be.

Steve





Re: Things that customers do that drive me nuts on CN

Roland Christen
 


As the peak error can be affected by any number of sporadic things (sudden spike in seeing, glitch in mount tracking etc),
The whole point of using Dec with guiding turned off is that it doesn't produce any guiding spikes because the axis is not moving and there is no guiding happening. All you see then is pure atmospheric motion which you want to avoid trying to chase.
You say that you have seen peak Dec errors of 3.71 arc seconds. Well the fact is that this error happened in the past and the next measurement may show a different position of the star, but the guiding software will still try to move the mount by that amount of distance, even though the actual star position may now be in the opposite direction.

Rolando


-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Tue, Jul 10, 2018 9:46 am
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN



Hi Bill,

I wanted to come back to the "right" way to use GA to determine the MinMo values, as I agree it is critical that these be set correctly.

Specifically for setting DEC MinMo you wrote:

>Look at Peak DEC error. It gives it to you in both pixels (which you need for PHD MinMo) and Arc-Seconds (which you need to talk to people with).
>Set MinMo to Peak DEC error value GA gave you

I'm not sure if you really meant "peak" here.  ; I've uploaded a screen grab of my calibration run last night.  During GA the measured peak DEC error was 1.25px or 3.71 arc-s.  As the peak error can be affected by any number of sporadic things (sudden spike in seeing, glitch in mount tracking etc), I don't think it provides the right baseline to set DEC MinMo.  

The RMS number gives a better measure.   I have seen suggestions to set MinMo to 2x the RMS  which was 0.12 px / 0.36 arc-s for me, so that would have put my DEC MinMo at 0.24 px.  Perhaps the right multiplier needs to be bigger at 3x or even 4x the RMS.

As I mentioned in an earlier post, Bruce already agreed that the current MinMo recommendations can be too optimistic/aggressive.  Having PHD2 come up with more realistic recommendations will help (especially beginners) get off to a good start.

Steve





Re: Things that customers do that drive me nuts on CN

Stephen Winston
 

Hi Wade,

>Let the mount run unguided for a few minutes while watching the graph.  Throw out any really big outlier values and take the peak from what is left.  

This, ideally, is exactly what PHD2 GA should be doing, right?  And it should be what GAs recommendations are based on.  Now I haven't looked to see how PHD2 generates it's GA recommendations, but as I mentioned below I believe it's something the PHD2 team is looking at as a result of this investigation.

>Taking the RMS seems like it would guarantee that the mount is going to chase seeing.

To be clear, the general recommendation I have seen is to use some multiplier of the RMS value, not the RMS value as-is.

Steve


Re: Things that customers do that drive me nuts on CN

Stephen Winston
 

Hi Roland,

I just responded to Bill on this before seeing your post.

RMS is a measure of error from the predicted data, which in this case is the error with respect to straight line tracking, I would have thought? So isn't the RMS primarily determined by the variation ("error") caused seeing?  But maybe I'm misunderstanding how PHD2 calculates this value.

Anyway, the max DEC error I see with guiding turned off can vary greatly.  I just uploaded a screen grab from last night's GA calibration run.  The reported peak DEC error was 3.71 arc-s or 1.25 px.  I think using that as the DEC MinMo would be overly pessimistic.

The problem with using the peak value is that is is susceptible to random worst case scenarios: sudden huge spike in seeing, piece of dirt in DEC worm, moth landing on the camera :).  It doesn't necessarily give a good idea of what the average seeing or tracking will be.

Steve



Re: Things that customers do that drive me nuts on CN

Roland Christen
 

One thing I would like to see is to do rapid corrections after a dither so that the star is brought back to zero quickly, after which the rate of corrections can be slowed down. The way things work now, if you have 10 second guide exposures, it might take 40 to 60 seconds for the mount to fully settle after a dither move.

Rolando



-----Original Message-----
From: 'Ray Gralak (Groups)' groups3@... [ap-gto]
To: ap-gto
Sent: Tue, Jul 10, 2018 7:19 am
Subject: RE: [ap-gto] Re: Things that customers do that drive me nuts on CN

Hi Craig,

I'll have to take a look at how Prism is using a (presumably 2D) FFT but I think that's still a 20th century technique. The advancements I am talking about do not concern the identification of the stars but in trying to predict guiding behavior based on deep learning techniques using many different variables including telescope load, position, pier side, changing seeing conditions, etc., all learned from previous mechanical behavior under the various conditions. By using deep learning techniques the software should be able to self-adapt the guiding behavior based on what it has learned under the various constraints.

-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: Monday, July 9, 2018 9:17 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN
>
>
>
> I used Maxim with my AP900 up until about three years ago and it guided well most of the time, but I abandoned
> it due to crashes/hangs and issues I had trying to get support. After that I switched to TheSkyX and had good
> results with their auto guiding- both with and without CCD AP- at least as good as Maxim. Last year I upgraded
> to an AP1600 which also guided well with TheSkyX. Lately I’ve been using Prism with the AP1600 after installing
> it to help a friend and have been very impressed with it’s auto guiding capabilities- lots of control including support
> for different settings on each axis, nice handling of hot pixels, and a multi-star guiding mode that seems to provide
> the best results for my setup.
>
> I really like what Innovation Foresight is doing with their auto guiding technology, I think they’re using FFT instead
> of stars. They had a very impressive demo set up at NEAF showing how their algorithm can auto guide even
> when stars in the guider FOV just about fade to the point where they blend into the background noise.
>
>
> -Craig
>
>
>
> On Jul 9, 2018, at 11:56 PM, 'Ray Gralak (Groups)' groups3@gralak..com <mailto:groups3@...>
> [ap-gto] gto@...> wrote:
>
>
> Hi Bill,
>
> > options. I have Sky X, but haven't heard much about its guiding.
>
> The Bisque's have been doing astro software probably longer than anyone. CCDSoft V5 autoguiding was
> generally considered to be very
> good, at least on par with MaxmDL's . I think that CCDSoft has evolved to be the camera add on to SkyX,
> so I would expect similar,
> if not improved performance.
>
> Please post any observations once you've had a chance to use it for a while..
>
> 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 <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: Monday, July 9, 2018 8:45 PM
> > To: ap-gto@yahoogroups..com <mailto:ap-gto@...>
> > Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN
> >
> >
> >
> > I've never used Maxim but I would suspect it does a great job of guiding. I use PHD, but I'm exploring
> other
> > options. I have Sky X, but haven't heard much about its guiding.
> > ________________________________
> >
> > From: ap-gto@... gto@...> on behalf of 'Ray Gralak (Groups)'
> > groups3@... [ap-gto] gto@...>
> > Sent: Monday, July 9, 2018 8:38:27 PM
> > To: ap-gto@yahoogroups..com <mailto:ap-gto@...>
> > Subject: RE: [ap-gto] Re: Things that customers do that drive me nuts on CN
> >
> >
> >
> > What I don't get is why some think that the mount is entirely the problem. I think that the autoguiding
> software is
> > at least part of the problem here. Autoguiding is not easy and can be extremely unpredictable.
> >
> > MaximDL has been refining algorithms for 20+ years so I am pretty sure they have an order of magnitude
> more
> > experience testing and developing (trade secret) autoguiding techniques than the entire PHD2 team
> combined.
> > Yet, I do not think that MaximDL's autoguiding algorithms are able to predict all unexpected conditions.
> >
> > Last year I discovered a couple of bugs in PHD2 in the course of one evening of testing. I can only guess
> that
> > most of the current developers who work on this software are doing it for fun. The guiding techniques
> > incorporated are nothing really new so it is not surprising that the PHD2 forum is often ripe with people
> with
> > guiding problems.
> >
> > Case in point is the current dec oscillation issue. Actual declination drift *very* seldom changes direction
> in the
> > sky so if the mount is operating correctly the guiding software should very seldom need to issue a
> reverse
> > direction move. Yet the software does... and way too often in some cases! Now this may just be a
> configuration
> > issue but you can't expect a user to babysit the parameters and know how to change them when seeing
> changes
> > or the mount is flipped to the other side of the pier.
> >
> > I think new approaches to autoguiding are needed to move autoguiding out of 20th century techniques.
> >
> > -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: Monday, July 9, 2018 7:51 PM
> > > To: ap-gto@...
> > > Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN
> > >
> > >
> > >
> > > >No, it tells everyone to guide at 0.2 MinMo.
> > >
> > >
> > > BTW: Not to be picky, but this is not actually true. If you run the Guiding Assistant it will recommend a
> range of
> > > values based on what it measures on your mount / local seeing conditions. PHD2 often "recommends"
> MinMo
> > or
> > > 0.15 or even 0.10 for my mount, but I have been sticking with 0.20.
> > >
> > >
> > > You'll see on the PHD2 forum thread that Bruce (one of the PHD2 developers) already acknowledged
> that those
> > > recommendations are overly optimistic and I hope they will address that in a future update.
> > >
> > >
> > >
> > > I believe that 0.20 is the "default" setting if you have not run Guiding Assistant to characterize your
> specific
> > > mount/conditions.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
>
>



------------------------------------
Posted by: "Ray Gralak \(Groups\)" <groups3@...>
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Re: Things that customers do that drive me nuts on CN

W Hilmo
 

Let the mount run unguided for a few minutes while watching the graph.  Throw out any really big outlier values and take the peak from what is left.  Taking the RMS seems like it would guarantee that the mount is going to chase seeing.

 

Seriously, if the mount is well polar aligned, the only thing that you want to correct for in declination is a fairly small amount of drift.  The drift should be slow, consistent, and always in the same direction.  If the declination guider is constantly issuing corrections, or (especially) changing directions frequently, then you are chasing seeing.  You really want to be having infrequent corrections.

 

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, July 10, 2018 7:45 AM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN

 

 

Hi Bill,

 

I wanted to come back to the "right" way to use GA to determine the MinMo values, as I agree it is critical that these be set correctly.

 

Specifically for setting DEC MinMo you wrote:

 

>Look at Peak DEC error. It gives it to you in both pixels (which you need for PHD MinMo) and Arc-Seconds (which you need to talk to people with).

>Set MinMo to Peak DEC error value GA gave you



I'm not sure if you really meant "peak" here.  I've uploaded a screen grab of my calibration run last night.  During GA the measured peak DEC error was 1.25px or 3.71 arc-s.  As the peak error can be affected by any number of sporadic things (sudden spike in seeing, glitch in mount tracking etc), I don't think it provides the right baseline to set DEC MinMo.  



The RMS number gives a better measure.   I have seen suggestions to set MinMo to 2x the RMS  which was 0.12 px / 0.36 arc-s for me, so that would have put my DEC MinMo at 0.24 px.  Perhaps the right multiplier needs to be bigger at 3x or even 4x the RMS.



As I mentioned in an earlier post, Bruce already agreed that the current MinMo recommendations can be too optimistic/aggressive.  Having PHD2 come up with more realistic recommendations will help (especially beginners) get off to a good start.

 

Steve

 

 


Re: Things that customers do that drive me nuts on CN

Roland Christen
 


Still doesn't explain why on one side of the meridian the mount + PHD2 has no problem guiding for hours with a 0.20 MinMo.

If not stiction, then what is causing the massive over corrections coupled with the fact that it take multiple guide pulses before the mount starts to respond?
You may have a different mechanical load on the mount axis on one side versus the other. If on one side the cabling impedes movement of the axis but on the other side it does not, then you may get different guiding actions.

People always forget how small one arc second is. On a 6" worm wheel a 1 arc sec movement will advance the wheel by .0000072 inches. That's 184 nanometers which is about 1/3 of the wavelength of light. And you want to set the MinMove to approximately 1/3rd of that which would be 61 nanometers which is getting into some very small motions. A human hair would be the size of a house in comparison.

Rolando


-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Mon, Jul 9, 2018 10:37 pm
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN



>Not in my use of the software it doesnt. It suggests things you should not do, at all, ever.  
>Like set your MinMo to 0.2 (or 0.18, 0.11, 0.10, 0.13) as you did.

Bill, I can only assume you still haven't read the full PHD thread and are just picking isolated sections of guide graphs to share here.

First: In the section you posted when I was deliberately changing the MinMo all the way down to 0.10, I was explicitly demons trating for the PHD2 team that the oscillations were not being caused by a dragging cable.  With MinMo set to 0.3, PHD2 will indeed ignore most of the seeing, and hence not generating any guide corrections.  If there had been a dragging cable causing the DEC spikes it would have been seen - but it was not.  WIth MinMo set to a more aggressive level, PHD2 starts generating guide pulses (yes, chasing the seeing) but these guide pulses trigger an immediate and repeating over correction.

I will upload the complete guide logs so others can have the full view of what is going on and make their own conclusions.


>This is a problem with you accepting what the GA told you to do, which was wrong, and not using the advice of the person that made the mount. 

GA recommended 0.15 and I used 0.20.  Is 0.20 overly optimistic for my seeing conditions?  Perhaps.  

Still doesn't explain why on one side of the meridian the mount + PHD2 has no problem guiding for hours with a 0.20 MinMo.

If not stiction, then what is causing the massive over corrections coupled with the fact that it take multiple guide pulses before the mount starts to respond?

Steve





Re: Things that customers do that drive me nuts on CN

Stephen Winston
 

Hi Bill,

I wanted to come back to the "right" way to use GA to determine the MinMo values, as I agree it is critical that these be set correctly.

Specifically for setting DEC MinMo you wrote:

>Look at Peak DEC error. It gives it to you in both pixels (which you need for PHD MinMo) and Arc-Seconds (which you need to talk to people with).

>Set MinMo to Peak DEC error value GA gave you


I'm not sure if you really meant "peak" here.  I've uploaded a screen grab of my calibration run last night.  During GA the measured peak DEC error was 1.25px or 3.71 arc-s.  As the peak error can be affected by any number of sporadic things (sudden spike in seeing, glitch in mount tracking etc), I don't think it provides the right baseline to set DEC MinMo.  


The RMS number gives a better measure.   I have seen suggestions to set MinMo to 2x the RMS  which was 0.12 px / 0.36 arc-s for me, so that would have put my DEC MinMo at 0.24 px.  Perhaps the right multiplier needs to be bigger at 3x or even 4x the RMS.


As I mentioned in an earlier post, Bruce already agreed that the current MinMo recommendations can be too optimistic/aggressive.  Having PHD2 come up with more realistic recommendations will help (especially beginners) get off to a good start.


Steve




Re: Things that customers do that drive me nuts on CN

Roland Christen
 


If you use Roland's suggestion of determining the peak DEC error, setting MinMo to that, and moving on with life

My RMS DEC error in last night's guiding session on the "good" side of the meridian was 0.17 pixels / 0.52". 
Peak error and RMS error are not related in any way. Measure your peak error (with Dec not correcting) and set the MinMove using that measurement. RMS error has no meaning when setting the MinMove. The whole point of setting this is to prevent chasing the seeing.

As soon as you set the MinMove to a very low value the software will issue large number of corrections which will begin to bounce the axis back and forth but without actually correcting the slow drift that occurs in the Dec axis. Ideally the Dec axis should be nudged back to the zero line by the guiding software as it slowly drifts either north or south. It should not be yanked back and forth in a vain effort to correct for every small movement of the atmosphere.

Rolando


-----Original Message-----
From: stephenjwinston@... [ap-gto]
To: ap-gto
Sent: Mon, Jul 9, 2018 8:55 pm
Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN



Hi Bill,

>Since we do not know the scale of the guiding solution you use, that is not very helpful.

Fully agree.  Again, this is actually something I have been debugging with the PHD2 guys.  All the information and detailed calibration and guide logs are there.  As mentioned in my first post above, I was avoiding discussing it here until I had completed debugging with them, but Roland opening up this thread pulled me in :).

My guider scale is: Pixel scale = 2.97 arc-sec/px, Binning = 1, Focal length = 514 mm
My imaging scale is: Pixel scale = 1.51 arc-sec/px, Binning = 1, Focal length = 735 mm

>setting your MinMo to a larger value (i.e. 0.1 to 0.3) is somehow stopping your guiding in DEC altogether. Why do you say this?

Again, this was all done in the context of testing/debugging the issue.  Setting MinMo to 0.1 triggers PHD2 to issue frequent guide pulses, triggered by seeing.  On one side of the meridian (and only one side) these corrective guide pulses trigger large oscillations that are not seen on the other side of the meridian.  Setting MinMo to 0.3 basically eliminates seeing triggered corrections (for my local seeing) and again this was done to demonstrate that the oscillations were not being triggered by something external like a dragging cable. Hope that makes sense.

>PHD cannot possibly have a "standard recommended MinMo"< span style="font-family:Calibri, Helvetica, sans-serif;font-size:16px;word-spacing:normal;"> 
Of course.  0.2 is the standard recommendation it makes for my imaging train based on my guiding pixel scale and based on the GA run that measures high frequency RMS and backlash in my mount.  Other peoples' recommended settings will of course vary.

>If you use Roland's suggestion of determining the peak DEC error, setting MinMo to that, and moving on with life

My RMS DEC error in last night's guiding session on the "good" side of the meridian was 0.17 pixels / 0.52".  Yes, I could set it to 0.3 or better 0.4 to ensure it never triggered an oscillation when guiding on the "bad" side of the meridian, but as you can tell from the guiding scale I'm using, 0.4 or even 0.3 is not what I'd expect from this mount, and as I keep repeating :), I get a whole lot better on one side of the meridian.

In retrospect, I probably shouldn't have responded to Rolando's post here and stuck to my original plan of completely debugging with the PHD guys first.
 
As I have mentioned in posts on the P HD forum and on CN, I believe that this is most likely a stiction problem (that's what the graph appear to show).  If that is the conclusion I come to with the PHD team (i.e. it's not some weird bug in PHD that only manifests on one side of the meridian), then my next step wiill be to dismantle DEC, give it a good cleaning/re-greasing, re-mesh the worm and see if that helps.

Once all that is done I'll report back here and on CN with my findings.

Steve