Mount Not Responding to Pulse Guiding Error Message

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Mark McComiskey

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Apr 1, 2024, 2:03:51 PM4/1/24
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I am getting a "PulseGuide command to mount has failed - guiding is likely to be ineffective." error message.  I'm new to guiding, and am having some trouble telling why this would be happening.  Guiding worked fine on this mount before, but the mount software was recently updates (the mount is an ASA DDM100), so perhaps that has created some issue?

I also sometimes, not always, the following note:

22:22:03.726 23.826 12152 Invalid mount guide speeds: RA: 0.0083, Dec: 0.0083
22:22:03.727 00.001 12152 Alert: The mount's ASCOM driver is reporting invalid guide speeds. Some guiding functions including PPEC will be impaired. Contact the ASCOM driver provider or mount vendor for support.

I should say that the mount guides beautifully well using ASA's own guiding software, but since that is incompatible with any other imaging control software, I very much want to use PHD2.

Attaching a log that contains both errors.

Any guidance or help would be much appreciated.


PHD2_DebugLog_2024-03-14_220519.txt

Bruce Waddington

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Apr 1, 2024, 4:10:39 PM4/1/24
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Hi Mark.  Could you please post both the guide and debug log file for this session rather than just the debug log file.  Use the built-in log uploading function in PHD2:
It's clear that the driver is buggy but we can give you more info once we have both log files.  In the meantime, if you can revert to the previous (non-Alpaca) version of the driver, you will probably be able to move ahead.

Bruce

Mark McComiskey

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Apr 1, 2024, 6:23:05 PM4/1/24
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I apologize - I am an idiot.  Logs uploaded and here is the link: https://openphdguiding.org/logs/dl/PHD2_logs_hWpW.zip

Bruce Waddington

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Apr 1, 2024, 11:04:43 PM4/1/24
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No, you're not an idiot, you haven't even come close. <g>

It looks like the developers of the new mount driver have made a hash of things with regard to pulse-guiding.  You have two problems here; 1) the reported mount guide speed that appears bogus and 2) the failure to pulse-guide.  The reported guide speed translates to 2x sidereal which I assumed was a basic error in reporting the value.  But when I look at the results from the calibration, 2x sidereal is what is actually being used!  This is a mess, you absolutely don't want to use guide speeds greater than 1x sidereal.  Doing so suddenly brings RA backlash into play, a topic we can fortunately ignore for all mounts.  That's the first sign of trouble.  Second, the pulse-guiding alert is being generated because the driver is never reporting that the command was successfully completed.  PHD2 uses a timeout factor of 2 seconds + the duration of the pulse-guide and your driver is routinely generating timeouts.  PHD2 will keep trying to guide but with this problem there's no way to know whether the guide command was processed correctly or not.  Both of these things need to be fixed and as I suggested, you may want to crawl back from the bleeding edge on this driver project and use the older driver for your mount.

One other thing that I found puzzling is that you never let the guiding run even after getting a reasonable calibration.  Why not?  The guiding was actually off to a pretty good star so why did you pull the plug?

Good luck,
Bruce

Mark McComiskey

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Apr 2, 2024, 8:56:26 AM4/2/24
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Thanks much for the information.  I was surprised by the guide speed as well, though lowering it didn’t solve the problem. The mount is a direct drive mount, which they advertise at least as not having any backlash due to the nature of direct drives.   I wonder if that is why they use a higher guide speed?  In the absence of backlash concerns, would the 2x sidereal work?


From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bruce Waddington <bw_m...@earthlink.net>
Sent: Monday, April 1, 2024 23:04
To: Open PHD Guiding <open-phd...@googlegroups.com>
Subject: [open-phd-guiding] Re: Mount Not Responding to Pulse Guiding Error Message
 
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Brian Valente

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Apr 2, 2024, 10:22:34 AM4/2/24
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>>>  I wonder if that is why they use a higher guide speed?  In the absence of backlash concerns, would the 2x sidereal work? 

 Mark I think the 2x reported speed is an error, not the actual guidespeed: you don't want to guide above 1x sidereal, otherwise you introduce reversals in the RA

Also it really shouldn't be necessary on a high end mount like the ASA. Their specs claim Tracking Accuracy (20° to 85°) <0,25” RMS within 5 minutes tracking time over 5 min 0,05” RMS/min

A mount of this caliber shouldn't need aggressive guiding

Given they just came out with their ASCOM driver recently, it seems more likely it's a software issue that should be addressed in their driver.



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Bruce Waddington

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Apr 2, 2024, 1:12:46 PM4/2/24
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I don't know whether 2x sidereal would work for guiding but it's a bad idea.  At that speed, you have to reverse direction of the RA axis and all the load it carries.  Direct drive systems are no different in that respect and all the ones I know about guide at or below 1x sidereal.  I think you should assume the driver is simply fouled up and needs to be repaired.

Bruce

mccom...@gmail.com

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Apr 2, 2024, 1:54:04 PM4/2/24
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Yes, of course.  If I had thought about that question for half a second, I could have answered it myself.  Basic mechanics.  Thanks.

mccom...@gmail.com

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Apr 2, 2024, 2:28:07 PM4/2/24
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I thought the same, but the guide speed in their mount software is set at 30 arc seconds/second.  I can change it back to 15 manually, so that isn’t a problem.  I’ve asked why they set it so high, but software support from ASA is…lacking, so I may never receive an answer.

 

Agreed, aggressive guiding should not be needed.  The old default settings for this mount were 6s/s.

mccom...@gmail.com

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Apr 2, 2024, 3:46:28 PM4/2/24
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Thanks.  Both logs are already uploaded.  I did run the Wizard.  24”RC on a GEM mount, operating at 2688 using an OAG.

 

From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> On Behalf Of Jens Scheidtmann


Sent: Monday, April 1, 2024 2:30 PM
To: open-phd...@googlegroups.com

Subject: Re: [open-phd-guiding] Mount Not Responding to Pulse Guiding Error Message

 

Dear Mark,

 

Please upload both Guide and Debug log using the procedure described here: 

This will help the experts here give much better advice. 

 

Please also provide a short description of your setup, including focal lengths of both imaging and guiding scopes. Also include if you‘re using an off-axis-guider or a rotator.

 

Wildly guessing on the description of your problem: 

Did you use the Wizard to create a new profile? It is run automatically on first startup and a lot of people skipping it do not enter a focal length for their guidescope. 

 

Sometimes people also enter the focal length of their main scope, instead of the guidescope focal length.

 

When you upload the logs, we‘ll be able to tell…

 

Best, Jens

 

 

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Brian Valente

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Apr 2, 2024, 3:54:41 PM4/2/24
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Does this mount have true absolute encoders as well? If so, it should be guided as an encoder mount

On Tue, Apr 2, 2024 at 5:56 AM Mark McComiskey <mccom...@gmail.com> wrote:
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mccom...@gmail.com

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Apr 2, 2024, 5:36:11 PM4/2/24
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Yes it does have absolute encoders.

 


Sent: Tuesday, April 2, 2024 3:54 PM
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Brian Valente

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Apr 2, 2024, 9:18:22 PM4/2/24
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Guiding encoder mounts is covered in this video (it's from astro-physics but applies to pretty much any encoder mount)


If you guide with 'regular' PHD2 defaults it probably won't be anywhere as good

 



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