Date   

Message Recall Failure: Recall: [ap-gto] APCC Pro MGBOX GPS connection #APCC

fl.lusen
 


Re: Notified!😍 #mach2gto #Mach2GTO

Terri Zittritsch
 

On Tue, Mar 10, 2020 at 02:44 PM, uncarollo2 <chris1011@...> wrote:
You should be able to get polar alignment good enough and keep it so with a solid tripod. Once aligned, I have not seen a tripod change the polar alignment.
 
Good polar alignment for imaging should result in Dec drift of 1 arc sec per 10 minutes at the meridian. If you also drift align the RA at the zenith, you should then also get 1 arc sec or better drift in 10 minutes for up to 2 hours on either side of the zenith. In PHD2 you can monitor your drift using the Trend Lines. You can then make tiny adjustments to the Alt and Az while watching the trend Lines and eventually zero in on perfect PA. Do the Azimuth first until the Dec line becomes flat - ignore the RA. Then tweak the Altitude until the RA line becomes flat. Do it on an overhead star. You might have to iterate a couple of times to get both Trend lines flat for at least 5 minutes. 
 
Thank you Rolando, I will give it a try next time I'm out.  You know, whenever I setup, I wonder just how stable things are.   My tripods by themselves are generally stable    But if for instance, a tripod foot settles 1mm, this can result in a 4 arc minute change in the polar pointing (referring to C. Woodhouse in the Astrophotography manual), I haven't done the calculations myself to validate this, but seems reasonable given the minuet changes required to get polar aligned (present incredibly poor accuracy aside).   Now that I've looked into it a bit, seems many people get amazingly good polar alignment results and not sure why mine is off so much (indicating as much as 5 minutes off the pole) when I am very careful in the process.     And just thinking about what it's doing, I'm not sure what could drive the inaccuracy except an incorrect refractive compensation.    In any case, some work for me to do.   Thanks again.


Re: Mach1 Unable to Find Home Position Suddenly

Ray Gralak
 

Hi Mikko,

I'm glad the problem is solved but I don't think that re-installing the driver had anything to do with that. The driver has fixed Hour angle/Declination positions for the park positions which would not have changed by reinstalling the driver.

BTW, when you say "Home Position", did you mean "Park Position"? With APCC you can define a home position but the AP V2 ASCOM driver doesn't have a "find home" feature.

-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: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Mikko Viljamaa
Sent: Tuesday, March 10, 2020 5:00 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Just an update. I "played" with the mount today and more I slew it, the further it missed the home position. Then I
uninstalled and reinstalled the driver and the problem disappeared. I slew it half a dozen times and every time it
returned home correctly. Go figure...


- Mikko


Re: Mach1 Unable to Find Home Position Suddenly

Mikko Viljamaa
 

Just an update. I "played" with the mount today and more I slew it, the further it missed the home position. Then I uninstalled and reinstalled the driver and the problem disappeared. I slew it half a dozen times and every time it returned home correctly. Go figure...


- Mikko


Re: SkySafari 6 connect to CP3

William
 

There is no # after the $$$.  SkySafari from my android phone sends $$$:V# when I connect to an Astro-Physics mount.
I changed the mount to Classic Meade LX200 and the $$$ is sent but then SkySafari just starts querying for RA and DEC.  This works with the AP CP3. 
I talked to someone who also uses SkySafari on an AP CP3 and he had to switch Bluetooth adapters to get it to work.  I don't have the bluetooth he does.  I believe if there is a slight delay between the $$$ and :V# the CP3 will work.

I have a serial test program that I wrote and if I send $$$:V# the CP3 does not respond.
Why is $$$ being sent is beyond me.  Just another case of a programmer not knowing how something really works.

Anyway I got it to work using the telescope set to Classic Meade LX200.

William 


Re: SkySafari 6 connect to CP3

jimmyjujames
 

 
$$$#:V# should work
The first $$$# clears an invalid command with no results returned
Then :V# will return version

The number 1 is infinitely larger than the number 0
Jimmy


Re: SkySafari 6 connect to CP3

Woody Schlom
 

William,

 

Another thought.  Have you “messed with” any of the DIP switches on the RN-270/SkyBT device?  The default switch positions work.  You don’t need to switch any of them.  All 4 DIP switches should be slid towards the red power button and DB-9 connector.

 

Woody

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of uncarollo2 <chris1011@...> via Groups.Io
Sent: Tuesday, March 10, 2020 11:51 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] SkySafari 6 connect to CP3

 

 

$$$:V#

I'm pretty sure that's not a command. I believe it should be $V#

 

Rolando

 

 

-----Original Message-----
From: William via Groups.Io <werison@...>
To: main <main@ap-gto.groups.io>
Sent: Tue, Mar 10, 2020 7:41 am
Subject: [ap-gto] SkySafari 6 connect to CP3

When I try and connect SkySafari 6 to my AP 900 GTOCP3 firmware V2 the mount does not respond.
The data being sent is $$$:V# what does the $$$ command do?  I am using a serial bluetooth adapter that works great with other programs.
Looks like the CP3 is ignoring the :V# command if $$$ is preceding it.

Thanks,
William


Re: SkySafari 6 connect to CP3

jimmyjujames
 

Long shot
 
Some of my Linux scripts are set to display end of line (eol) as a $ sign.
 
I don't think LX-200 protocol uses an (EOL) character
# sign is the EOL in LX-200 protocol
$ sign may be an invalid character in this protocol
 
$$$:V# That may be 3 <returns> and then :V# (as you said is an invalid command with no results returned)
 
What software sent that command.
 
Has it had a upgrade lately which sometimes resets your setup.
 
I don't see where a Time change would cause this problem either, But
 
As always I may be wrong again.
Jimmy
 


Re: SkySafari 6 connect to CP3

Woody Schlom
 

William,

 

Although I haven’t used this combination in a long time, in the past I have successfully used SkySafari to control my Mach1 with CP3.  And I used it with a RN-270 Serial to Bluetooth adapter (Identical to SkyBT).

 

Woody

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of William via Groups.Io
Sent: Tuesday, March 10, 2020 10:41 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] SkySafari 6 connect to CP3

 

When I try and connect SkySafari 6 to my AP 900 GTOCP3 firmware V2 the mount does not respond.
The data being sent is $$$:V# what does the $$$ command do?  I am using a serial bluetooth adapter that works great with other programs.
Looks like the CP3 is ignoring the :V# command if $$$ is preceding it.

Thanks,
William


Re: SkySafari 6 connect to CP3

Roland Christen
 

Yes, you are correct. There is no $V# command.
 
Roland
 
 

-----Original Message-----
From: William via Groups.Io <werison@...>
To: main <main@ap-gto.groups.io>
Sent: Tue, Mar 10, 2020 9:08 am
Subject: Re: [ap-gto] SkySafari 6 connect to CP3

I know :V# will return the firmware version.  Never seen $V#.
When I send $V# nothing is returned from the CP3.

William


Re: SkySafari 6 connect to CP3

William
 

I know :V# will return the firmware version.  Never seen $V#.
When I send $V# nothing is returned from the CP3.

William


Re: SkySafari 6 connect to CP3

Roland Christen
 

 
$$$:V#
I'm pretty sure that's not a command. I believe it should be $V#
 
Rolando
 
 
-----Original Message-----
From: William via Groups.Io <werison@...>
To: main <main@ap-gto.groups.io>
Sent: Tue, Mar 10, 2020 7:41 am
Subject: [ap-gto] SkySafari 6 connect to CP3

When I try and connect SkySafari 6 to my AP 900 GTOCP3 firmware V2 the mount does not respond.
The data being sent is $$$:V# what does the $$$ command do?  I am using a serial bluetooth adapter that works great with other programs.
Looks like the CP3 is ignoring the :V# command if $$$ is preceding it.

Thanks,
William


Re: Notified!😍 #mach2gto #Mach2GTO

Roland Christen
 

 
I wonder how much error results from using a tripod vs. a pier,  and then much variation I'll see throughout the night.    
You should be able to get polar alignment good enough and keep it so with a solid tripod. Once aligned, I have not seen a tripod change the polar alignment.
 
Good polar alignment for imaging should result in Dec drift of 1 arc sec per 10 minutes at the meridian. If you also drift align the RA at the zenith, you should then also get 1 arc sec or better drift in 10 minutes for up to 2 hours on either side of the zenith. In PHD2 you can monitor your drift using the Trend Lines. You can then make tiny adjustments to the Alt and Az while watching the trend Lines and eventually zero in on perfect PA. Do the Azimuth first until the Dec line becomes flat - ignore the RA. Then tweak the Altitude until the RA line becomes flat. Do it on an overhead star. You might have to iterate a couple of times to get both Trend lines flat for at least 5 minutes. 
 
Roland
 
 
-----Original Message-----
From: Terri Zittritsch <theresamarie11@...>
To: main <main@ap-gto.groups.io>
Sent: Tue, Mar 10, 2020 2:17 am
Subject: Re: [ap-gto] Notified!😍 #mach2gto #mach2gto

On Tue, Mar 10, 2020 at 01:59 AM, uncarollo2 <chris1011@...> wrote:
The RA and Dec drift rates indicate fairly large Polar Alignment error. It means your Polemaster is giving you a significant PA error for whatever reason. That's why I don't rely on electronic devices for polar alignment. If you want the drift rate to be zero, then you have to do drift alignment where you twiddle with the Alt and Az adjusters until the drift rates are zero (which is the definition and goal of drift alignment). Ray Graylack's Pempro does that without muss or fuss in surprisingly short time. Once I have drift alignment zeroed in, I simply attach my right angle Polar scope, place Polaris at the correct point on the dial via the push-pull adjustment and I'm good to go from then on using only the Polar scope. Of course with guiding the drift doesn't matter, but for best performance it is good to have essentially zero drift. Yerkes observatory did it in the late 1800's and they had some pretty crude methods with that 40" refractor mount. But it was good enough to allow unguided imaging for considerable time exposures.
 
Every generation of astro-imagers has to go thru this learning process, and the fundamentals never change. The 2.5 arc sec P-P excursions are almost exactly what the seeing was for that night, so that will be the best you will get under those conditions. No way anything less than a $1million active guiding system along with high power laser for forming an artificial star will do any better.
 
By the way, your Vermont skies are not too bad. In the last week I had 1.2 arc sec FWHM resolution with no guiding (simple model in the keypad only) for 2 nights, then the seeing morphed into 7.5 arc sec FWHM stars when the trade winds picked up. Sky was crystal clear but stars looked like small shaggy dogs.
 
Rolando
Thank you again Roland for your personal time here.    I think what you're telling me is that by drift aligning, and then adjusting your polar scope to put polaris in the correct position based on the drift alignment, that you're calibrating your polar scope for refraction effects at your location.   I guess you're actually moving your reticle to match where polaris is after drift aligning.   I know Polemaster is supposed to be able to account for some refractive effect, but likely not super-accurate and just some kind of calculated estimate.    Are you also saying that for a particular location, refractive effects are constant?

If the offset due to refractive effects is constant, then maybe I can estimate in polemaster.    Right now I have no idea what this might look like (how much).   I guess maybe a drift align one night with polemaster monitor running will give me my answer.     The other complication is that I have no pier or 100% stable setup.   I wonder how much error results from using a tripod vs. a pier,  and then much variation I'll see throughout the night.    


T


SkySafari 6 connect to CP3

William
 

When I try and connect SkySafari 6 to my AP 900 GTOCP3 firmware V2 the mount does not respond.
The data being sent is $$$:V# what does the $$$ command do?  I am using a serial bluetooth adapter that works great with other programs.
Looks like the CP3 is ignoring the :V# command if $$$ is preceding it.

Thanks,
William


Re: Lunar Tracking Rate #ASCOM_V2_Driver

Mike Miller
 

Ahh, that would do it! The only app I had connected was APJog, which I used for nudging.  In the future I will get the moon framed and disconnect APJog before hitting the button.

If I am gong to do some imaging instead of just a quick EAA, I will use Horizons to get the rates perfect. This was kind of a on-a-whim thing, and I was out in the field without internet access.

Thanks for your help!

-mike


Re: Notified!😍 #mach2gto #Mach2GTO

Terri Zittritsch
 
Edited

On Tue, Mar 10, 2020 at 01:59 AM, uncarollo2 <chris1011@...> wrote:
The RA and Dec drift rates indicate fairly large Polar Alignment error. It means your Polemaster is giving you a significant PA error for whatever reason. That's why I don't rely on electronic devices for polar alignment. If you want the drift rate to be zero, then you have to do drift alignment where you twiddle with the Alt and Az adjusters until the drift rates are zero (which is the definition and goal of drift alignment). Ray Graylack's Pempro does that without muss or fuss in surprisingly short time. Once I have drift alignment zeroed in, I simply attach my right angle Polar scope, place Polaris at the correct point on the dial via the push-pull adjustment and I'm good to go from then on using only the Polar scope. Of course with guiding the drift doesn't matter, but for best performance it is good to have essentially zero drift. Yerkes observatory did it in the late 1800's and they had some pretty crude methods with that 40" refractor mount. But it was good enough to allow unguided imaging for considerable time exposures.
 
Every generation of astro-imagers has to go thru this learning process, and the fundamentals never change. The 2.5 arc sec P-P excursions are almost exactly what the seeing was for that night, so that will be the best you will get under those conditions. No way anything less than a $1million active guiding system along with high power laser for forming an artificial star will do any better.
 
By the way, your Vermont skies are not too bad. In the last week I had 1.2 arc sec FWHM resolution with no guiding (simple model in the keypad only) for 2 nights, then the seeing morphed into 7.5 arc sec FWHM stars when the trade winds picked up. Sky was crystal clear but stars looked like small shaggy dogs.
 
Rolando
Thank you again Roland for your personal time here.    I think what you're telling me is that by drift aligning, and then adjusting your polar scope to put polaris in the correct position based on the drift alignment, that you're calibrating your polar scope for refraction effects at your location.   I guess you're actually moving your reticle to match where polaris is after drift aligning.   I know Polemaster is supposed to be able to account for some refractive effect, but likely not super-accurate and just some kind of calculated estimate.    Are you also saying that for a particular location, refractive effects are constant?

If the offset due to refractive effects is constant, then maybe I can estimate in polemaster.    Right now I have no idea what this might look like (how much).   I guess maybe a drift align one night with polemaster monitor running will give me my answer.     The other complication is that I have no pier or 100% stable setup.   I wonder how much error results from using a tripod vs. a pier,  and then how much variation this causes throughout the night.    


T


Re: PHD2 versus ASCOM driver

Terri Zittritsch
 

On Tue, Mar 10, 2020 at 02:51 AM, Wayne Hixson wrote:
Thanks Roland. Of your suggestions, I’ll I’ve done so far is add a 1500 ms delay between 3 second exposures and getting the best guiding I’ve ever seen by far as I am live stacking M94 in SharpCap.  About 0.5” RMS over at least an hour with only occasional tiny corrections. 0.32” RA and 0.34” Dec.  OAG with an Ultrastar binned 2x2, 130GTX with field flattener, or 871 mm fl. Love it!
 
PS I used the Polemaster about 4 hours ago and just checked, the little green Pole square is still overlapping the red axis target circle by about 33%. 
 
Enjoy your time in Hawaii and I am looking forwards to using the keypad for modeling!
 
Congratulations Wayne, this is great news!   I can't wait to try the updated settings.  I've never done the delay between pulses either, but it certainly makes sense.

Thanks to Roland for the guiding education, maybe I can finally stop overdosing myself when at the telescope now (smile).

T


Re: PHD2 versus ASCOM driver

 

FYI in recent releases, PHD can recognize if you are using encoders, and changes the default algorithm to lowpass2 for precisely the reasons Roland outlined

when you use the new profile wizard, it will calculate the correct step sizes, but it will not add time between your frames.

Wayne you might want to try bin 1 on your ultrastar. those are already pretty big pixels. Sounds like you have the time courtesy of the mount's accuracy that you can increase your exposure time if need be (and reduce time delay between exposures if need be)


Brian



On Mon, Mar 9, 2020 at 11:52 PM Wayne Hixson via Groups.Io <wayneh9026=yahoo.com@groups.io> wrote:
Thanks Roland. Of your suggestions, I’ll I’ve done so far is add a 1500 ms delay between 3 second exposures and getting the best guiding I’ve ever seen by far as I am live stacking M94 in SharpCap.  About 0.5” RMS over at least an hour with only occasional tiny corrections. 0.32” RA and 0.34” Dec.  OAG with an Ultrastar binned 2x2, 130GTX with field flattener, or 871 mm fl. Love it!

PS I used the Polemaster about 4 hours ago and just checked, the little green Pole square is still overlapping the red axis target circle by about 33%. 

Enjoy your time in Hawaii and I am looking forwards to using the keypad for modeling!

Wayne


On Mar 9, 2020, at 10:21 PM, uncarollo2 <chris1011@...> via Groups.Io <chris1011=aol.com@groups.io> wrote:


 
We have another clear night expected tonight before the rains return. Any suggestions on these issues specifically or settings for PHD2 more generally?
hello Wayne,
 
One setting I recommend for Encoder Mounts is to use a 1.5 to 2 second delay time between guide exposures. Click on the little brain in PHD2 and bring up the Advanced Setting/Camera Settings. Set the Time Lapse to 1500 to 2000. Your guide exposures can be set to anything from under 1 sec to 5 sec or more. I usually use 2 sec exposures unless the seeing is jumping around, in which case a longer exposure is used.
 
I normally use 1x Sidereal guide rate, but you can use .5x also if the seeing is good. There is no need to go slower to .25x.
 
Calibration steps are 300msec at 1x sidereal, 600msec at .5x.
 
I use either Lowpass 2 or Hysteresis. In Lowpass2 my settings are normally Aggressiveness 50 to 80% depending on seeing. Higher if good, lower if poor seeing. Min Move depends on seeing as reported in Guiding Assistant. Usually set to 0.2 pixels for my setup which has 2 arc sec per pixel. Max Duration is 2500msec. Both axes are set the same, no Backlash Compensation is used (set it to 0).
 
I have used all the other algorithms with success. Settings vary by scope focal length and seeing conditions. In all cases use a 1500 to 2000 Time Lapse in order to let the mount settle between guide exposures and not try to chase the seeing. An encoder mount will reverse Dec very accurately for even 1/4 arc sec move commands, but not in zero time. When the mount gets a very tiny Dec move command to reverse it will so in a controlled manner at a controlled rate. It is not instant, so the Time Lapse lets the Dec axis get there and settle before getting another small move command.
In a non-encoder mount there is a delay time, but also a crossover hysteresis where it may take 2, 3 or more small move commands before the axis actually reverses. This is different in an encoder mount where only 1 command is needed for full reversal, or any move deemed necessary by the software. For instance if the guide star is 1 arc sec off the centerline and Aggress is set to 100%, then the software sends a -1 arc sec move command, and the mount will move the axis exactly 1 arc sec, no more, no less.
In RA it's always instant because the belt tension (or gear mesh) is always on in the direction of movement. It simply slows down or speeds up. In Dec it's also instant if moving in the same direction each time, but takes some 100 +milliseconds when reversing.
Reversing Dec axis is like taking a Tylenol pill for a headache. You take 1 pill and wait for the headache to go away, and it will after a bit of time. If you don't wait and think I took one pill, still have the headache and take another and another until the headache goes away, you have overdosed yourself. The first one + time lapse delay was actually best for your health.
 
So for Dec we don't call it backlash since there isn't any when reversing. In encoder terms it's called Settling Time. There is even settling time for RA during dither recovery where the mount is commanded to move many arc seconds. For instance, if the dither is 15 arc seconds and the guide rate is 0.5x, it will take the mount approximately 2 seconds to get back to the zero line (0.5x = 7.5 arc sec per sec). If you have a guide rate set for 0.5 seconds with no Time Lapse delay dialed in, the mount will get numerous 15 arc second move commands and will indeed overshoot at the end.
 
Hope this helps.
 
Rolando
 
-----Original Message-----
From: Wayne Hixson via Groups.Io <wayneh9026=yahoo.com@groups.io>
To: main <main@ap-gto.groups.io>
Sent: Mon, Mar 9, 2020 9:05 am
Subject: [ap-gto] PHD2 versus ASCOM driver

Had a really good night with the Mach2 under clear but moonlit skies. PHD2 ran reasonable well with default settings, but  ran into a couple issues. First, it warned me I should disable Synchronous Pulseguide in the driver, I couldn’t find that setting and not sure I want to disable even if I could!

Second I had several times where I got a warning message that mount wasn’t responding to pulseguide commands and I had to disconnect/reconnect to resume.

We have another clear night expected tonight before the rains return. Any suggestions on these issues specifically or settings for PHD2 more generally?

wayne 



--
Brian 



Brian Valente


Re: PHD2 versus ASCOM driver

Wayne Hixson
 

Thanks Roland. Of your suggestions, I’ll I’ve done so far is add a 1500 ms delay between 3 second exposures and getting the best guiding I’ve ever seen by far as I am live stacking M94 in SharpCap.  About 0.5” RMS over at least an hour with only occasional tiny corrections. 0.32” RA and 0.34” Dec.  OAG with an Ultrastar binned 2x2, 130GTX with field flattener, or 871 mm fl. Love it!

PS I used the Polemaster about 4 hours ago and just checked, the little green Pole square is still overlapping the red axis target circle by about 33%. 

Enjoy your time in Hawaii and I am looking forwards to using the keypad for modeling!

Wayne


On Mar 9, 2020, at 10:21 PM, uncarollo2 <chris1011@...> via Groups.Io <chris1011@...> wrote:


 
We have another clear night expected tonight before the rains return. Any suggestions on these issues specifically or settings for PHD2 more generally?
hello Wayne,
 
One setting I recommend for Encoder Mounts is to use a 1.5 to 2 second delay time between guide exposures. Click on the little brain in PHD2 and bring up the Advanced Setting/Camera Settings. Set the Time Lapse to 1500 to 2000. Your guide exposures can be set to anything from under 1 sec to 5 sec or more. I usually use 2 sec exposures unless the seeing is jumping around, in which case a longer exposure is used.
 
I normally use 1x Sidereal guide rate, but you can use .5x also if the seeing is good. There is no need to go slower to .25x.
 
Calibration steps are 300msec at 1x sidereal, 600msec at .5x.
 
I use either Lowpass 2 or Hysteresis. In Lowpass2 my settings are normally Aggressiveness 50 to 80% depending on seeing. Higher if good, lower if poor seeing. Min Move depends on seeing as reported in Guiding Assistant. Usually set to 0.2 pixels for my setup which has 2 arc sec per pixel. Max Duration is 2500msec. Both axes are set the same, no Backlash Compensation is used (set it to 0).
 
I have used all the other algorithms with success. Settings vary by scope focal length and seeing conditions. In all cases use a 1500 to 2000 Time Lapse in order to let the mount settle between guide exposures and not try to chase the seeing. An encoder mount will reverse Dec very accurately for even 1/4 arc sec move commands, but not in zero time. When the mount gets a very tiny Dec move command to reverse it will so in a controlled manner at a controlled rate. It is not instant, so the Time Lapse lets the Dec axis get there and settle before getting another small move command.
In a non-encoder mount there is a delay time, but also a crossover hysteresis where it may take 2, 3 or more small move commands before the axis actually reverses. This is different in an encoder mount where only 1 command is needed for full reversal, or any move deemed necessary by the software. For instance if the guide star is 1 arc sec off the centerline and Aggress is set to 100%, then the software sends a -1 arc sec move command, and the mount will move the axis exactly 1 arc sec, no more, no less.
In RA it's always instant because the belt tension (or gear mesh) is always on in the direction of movement. It simply slows down or speeds up. In Dec it's also instant if moving in the same direction each time, but takes some 100 +milliseconds when reversing.
Reversing Dec axis is like taking a Tylenol pill for a headache. You take 1 pill and wait for the headache to go away, and it will after a bit of time. If you don't wait and think I took one pill, still have the headache and take another and another until the headache goes away, you have overdosed yourself. The first one + time lapse delay was actually best for your health.
 
So for Dec we don't call it backlash since there isn't any when reversing. In encoder terms it's called Settling Time. There is even settling time for RA during dither recovery where the mount is commanded to move many arc seconds. For instance, if the dither is 15 arc seconds and the guide rate is 0.5x, it will take the mount approximately 2 seconds to get back to the zero line (0.5x = 7.5 arc sec per sec). If you have a guide rate set for 0.5 seconds with no Time Lapse delay dialed in, the mount will get numerous 15 arc second move commands and will indeed overshoot at the end.
 
Hope this helps.
 
Rolando
 
-----Original Message-----
From: Wayne Hixson via Groups.Io <wayneh9026@...>
To: main <main@ap-gto.groups.io>
Sent: Mon, Mar 9, 2020 9:05 am
Subject: [ap-gto] PHD2 versus ASCOM driver

Had a really good night with the Mach2 under clear but moonlit skies. PHD2 ran reasonable well with default settings, but  ran into a couple issues. First, it warned me I should disable Synchronous Pulseguide in the driver, I couldn’t find that setting and not sure I want to disable even if I could!

Second I had several times where I got a warning message that mount wasn’t responding to pulseguide commands and I had to disconnect/reconnect to resume.

We have another clear night expected tonight before the rains return. Any suggestions on these issues specifically or settings for PHD2 more generally?

wayne 


Re: Notified!😍 #mach2gto #Mach2GTO

Roland Christen
 

 
In looking at my graph without guiding input, the center of my RA trace drifted around 6.25 arc seconds in 11 minutes (in RA).    In DEC, the trace shows only  about 3.75 arc seconds of drift in 11 minutes.      The peak to peak of the each graph was similar, and more than 2.5 arc seconds P-P.     I sent this to you in a screen shot.   I expect this is telling me that the seeing was poor at best, based on these values.
The RA and Dec drift rates indicate fairly large Polar Alignment error. It means your Polemaster is giving you a significant PA error for whatever reason. That's why I don't rely on electronic devices for polar alignment. If you want the drift rate to be zero, then you have to do drift alignment where you twiddle with the Alt and Az adjusters until the drift rates are zero (which is the definition and goal of drift alignment). Ray Graylack's Pempro does that without muss or fuss in surprisingly short time. Once I have drift alignment zeroed in, I simply attach my right angle Polar scope, place Polaris at the correct point on the dial via the push-pull adjustment and I'm good to go from then on using only the Polar scope. Of course with guiding the drift doesn't matter, but for best performance it is good to have essentially zero drift. Yerkes observatory did it in the late 1800's and they had some pretty crude methods with that 40" refractor mount. But it was good enough to allow unguided imaging for considerable time exposures.
 
Every generation of astro-imagers has to go thru this learning process, and the fundamentals never change. The 2.5 arc sec P-P excursions are almost exactly what the seeing was for that night, so that will be the best you will get under those conditions. No way anything less than a $1million active guiding system along with high power laser for forming an artificial star will do any better.
 
By the way, your Vermont skies are not too bad. In the last week I had 1.2 arc sec FWHM resolution with no guiding (simple model in the keypad only) for 2 nights, then the seeing morphed into 7.5 arc sec FWHM stars when the trade winds picked up. Sky was crystal clear but stars looked like small shaggy dogs.
 
Rolando
 
 
-----Original Message-----
From: Terri Zittritsch <theresamarie11@...>
To: main <main@ap-gto.groups.io>
Sent: Mon, Mar 9, 2020 1:45 pm
Subject: Re: [ap-gto] Notified!😍 #mach2gto #mach2gto

On Sun, Mar 8, 2020 at 05:31 PM, uncarollo2 <chris1011@...> wrote:
1) Polemaster does not necessarily insure good polar alignment. Only drift alignment can reduce drift.
 
2) Having perfect polar alignment does not insure zero drift due to atmospheric refraction
 
3) doing a drift alignment can produce zero drift for both RA and Dec if you use the right method, but this zero drift will only occur in the area around the zenith. In other parts of the sky the stars do not move at sidereal rate, and will also drift slowly in Dec. This is fundamental, and no amount of polar alignment will prevent drift.
 
4) In our new keypad software we have added the King rate which reduces the RA drift in those parts of the sky where the sidereal rate is incorrect, however the King rate does not address Dec drift. We have modeling software in the new keypad which can be used to compensate for drift in both axes, and can allow unguided imaging. You can also go full model with APCC Pro, but I would recommend using that for permanent setups where you can spend some time getting a really good all-sky model.
 
Rolando 
 
Hi Rolando,
In looking at my graph without guiding input, the center of my RA trace drifted around 6.25 arc seconds in 11 minutes (in RA).    In DEC, the trace shows only  about 3.75 arc seconds of drift in 11 minutes.      The peak to peak of the each graph was similar, and more than 2.5 arc seconds P-P.     I sent this to you in a screen shot.   I expect this is telling me that the seeing was poor at best, based on these values.   I was still getting round stars (while actively guiding).   Such is life in Vermont under the jet stream!

I'm happy to report that I've successfully installed APCC, and set it up and at least tested it out without any clear sky.    Everything connects as it should.    Called George today, who was very helpful, to provided guidance on some of the finer points.    Now just waiting for clear skies.

Terri