PHD guide while slewing

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Eric Esch

Sep 19, 2021, 12:54:19 PMSep 19
to Open PHD Guiding
Hey guys, I have a custom built fork and drive with a c8 running Onstep. It was guiding perfectly using older Onstep Ascom drivers, but I recently updated to the unified ascom driver package for Onstep so I could use my AutoFocuser. Now when I try and guide with phd2 i get a massive slew command from PHD2, then it fails that only explains that the scope is slewing. 
 here is my upload log:

AlsoI started a thread in the Onstep grojup about it and have found a few others having the same issue. 

here is a link to the onstep forum on it:

So i am not sure why this issue is arising now has this has guided perfectly in the past. Any insight would be helpful. 

Temp fixes we have found would be resetting the stepper rates and micro step shifting, but if that isnt done first we get these issues. Can PHD2 request a guide rate?


Sep 19, 2021, 4:51:36 PMSep 19
I would say your problem is probably with the ASCOM driver - not too surprising if that's the big change.  The driver appears to have numerous problems.  To start, ASCOM pulse-guiding specifies that the moves are done at whatever guide speed is set in the mount.  PHD2 never sets that nor should it - it's up to the user and there can be good reasons for using one speed vs. another.  If a pulse-guide command causes the mount to move by a huge amount as if it were slewing, that's probably a problem in the driver.  The driver should be responsible for choosing the correct speed for mount movement - e.g. guiding vs. slewing.  Next, you have a long string of failed calibrations, which you already know.  For the first 9 of these, the driver isn't even reporting basic info about the state of the mount: no guide speed, no RA, no Dec, no azimuth, no altitude, nothing.  Is the driver even initialized?  Is it even talking to the mount?  When you see alert messages in PHD2 announcing that the scope started slewing, that's because the driver said it did - not because PHD2 asked it to. 
I think you need to roll things back to their absolute basics.  Forget using NINA, forget imaging, even forget trying to do a calibration.  Just use the PHD2 Manual Guide tool and the star-cross test until the mount will move consistently and predictably in all 4 directions.  When it doesn't, you can present your problem to whomever wrote the ASCOM driver and figure out what is going wrong.  If the driver generates log files - which it should - I would guess it will be be pretty easy to figure out.
Good luck,

From: [] On Behalf Of Eric Esch
Sent: Sunday, September 19, 2021 9:54 AM
To: Open PHD Guiding
Subject: [open-phd-guiding] PHD guide while slewing

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