PHD2 guiding with Adaptive optics (SXV-AO)

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Alex

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Jun 28, 2022, 2:31:22 PM6/28/22
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I am attempting to use AO unit from starlight express (SXV-AO) with PHD2 guiding software and have it set up with off-axis guider/camera. Everything gets connected with PHD2 without any error messages. I have an EQ6 mount (running through ASCOM) so when calibration happens first the AO mirrors get calibrated than the mount gets calibrated. However, during guiding it looks like the mount does not receive any “bump to centre” commands, because once the star drifts off centre so the mirrors of AO can no longer pick it up The guiding fails. I tried adjusting AO stepsize setting from 1 to 30 but nothing happens It still fails to bump it back to the centre of the mirror...

 If I disconnect AO without changing any other settings the mount starts to actively  follow the star by bumping it to where it needs to be in the centre of guiding crosshairs On the computer screen.....so what am I doing wrong, why can’t mount bumping get activated when the star drifts off centre when AO unit is connected as is performing initial guiding??

How do I troubleshoot this?

thanks, Alex

Bruce Waddington

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Jun 28, 2022, 2:34:40 PM6/28/22
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You need to submit your PHD2 log files so we can see what you're doing wrong.

Make sure the logs you send include the calibrations and also be sure your EQMOD ASCOM settings match this document:


Regards,
Bruce

Alex

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Jun 28, 2022, 4:31:59 PM6/28/22
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How do I generate PHD2 log files and where are they saved? If they are generated by default,  I can probably look them up somewhere on the computer from last night ?

Brian Valente

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Jun 28, 2022, 4:34:51 PM6/28/22
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Alex

read the instructions here:

the logs are generated automatically, you use the built-in log uploader in PHD (as described above)

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Alex

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Jun 28, 2022, 10:28:45 PM6/28/22
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Log attached, please take a look.
PHD2_GuideLog_SXV_AO.txt

Bruce Waddington

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Jun 28, 2022, 10:56:39 PM6/28/22
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I don't think we're making much progress here.  Both of us have asked you to use the PHD2 'Upload Logs' feature to upload *both* the log files *in their entirety*  - not just the parts you think are relevant.  So maybe you can take another swing at this, it's not difficult.  Even with what you sent I can see you didn't follow the instructions in the setup instructions for EQMOD - a link to those was included in the second reply, the one I sent you.  You're trying to guide the mount at a rate of 0.1x sidereal which is much too slow.  Finally, you've diddled around with the AO guiding parameters and have told PHD2 that it shouldn't start the bumping operation until the star has reach 99% of the range of the AO device - that makes no sense either. 

AO operation in PHD2 typically works very well but it is sophisticated and requires some learning. When the star is starting to drift outside the operating range of the AO device, PHD2 will start guiding with *both* the mount and the AO, using a mixing approach that will preserve your image even as the large corrections are being made.  This will restore the guide star to a more central position on the AO in a smooth trajectory.  At this point, you need to start over with a new profile which will restore all the guiding parameters to their default values - those will almost always get you reasonably close to effective guiding.  You should do that using the new-profile-wizard *after* you've fixed the guide speed setting in EQMOD.  And of course we need you to follow the requested log upload procedure to get further help.

Regards,
Bruce

Alex

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Jun 28, 2022, 11:38:19 PM6/28/22
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Okay will upload the log file entirely  I just had two different guiding setups during one night so I didn’t want people to mix them up but if you wish to I can...the first part of the log is just using a regular of_axis guiding  without AO the second part is with AO , I was just testing to see if  guiding settings  were sufficient enough and aggressive enough for the star to be in the centre and they were if I’m not using AO, but once I start using AO the Mount Fails to activate bump commands once the star starts to drift. 

Alex

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Jun 28, 2022, 11:40:50 PM6/28/22
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full log file

Bruce Waddington

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Jun 29, 2022, 2:33:08 PM6/29/22
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I've looked at your logs again and the problems are definitely those I mentioned before - especially the very bad change you made to the "bump percentage".  By the time this percentage is reached, the AO is close to its limit and the very slow mount response causes things to go downhill from there.  When you start over with a new profile, please don't modify any of the guiding parameters. In addition to the changes mentioned previously, you should also start out using 1-second exposures until you learn how all this stuff works and you should disable "star mass detection" (Advanced Settings/ Guiding Tab).  This will reduce the number of lost-star events you're getting which are further complicating things.  Once we get your baseline measurements after all the changes have been made, we can probably give you more advice. 

Good luck,
Bruce
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