Nitecrawler rotator, NINA and PHD2

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Kevin Quin

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Jun 30, 2023, 6:36:05 PM6/30/23
to Open PHD Guiding
I upgraded all my gear recently, and I"m struggling to get the rotator functions to work properly.  After a lot of trial and error, it seems like I need to leave the Reverse Rotation Direction checkbox in the Nitecrawler ASCOM driver unchecked, but I need to check the Reverse Sign of Angle box in PHD2 Advanced Settings>Other Devices.  Does that sound correct?

In my testing, if I checked the Reverse in ASCOM, the rotator kept hunting for the proper angle and never found it, so I never got to PHD2 at all.  When I left Reverse unchecked in ASCOM, the rotator would find the proper angle, but PHD2 wouldn't issue the correct guiding commands, so the guide star moved in circles.  Next chance I get I'll try it with Reverse Sign of Angle checked.

Kevin

Bruce Waddington

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Jun 30, 2023, 11:53:03 PM6/30/23
to Open PHD Guiding
I think you've left out an important element in this software chain - NINA.  I think NINA has its own "reverse angle" option for a rotator and as I recall, they changed the polarity convention they are using sometime in the recent past.  So you've probably got three cooks in the kitchen here, all trying to decide if a single boolean option should be true or false.  Assuming NINA wants to control the rotator for purposes of framing, I would start there - figure out how to set the 'reverse angle' option in NINA so the rotator moves in the sky direction it wants.  Start with all the 'reverse' options being false then figure out what NINA wants.  Once NINA and the rotator are working well together, connect PHD2 to the rotator and see if PHD2 can correctly adjust the calibration when the rotator is moved.  If not, change the 'reverse' option in PHD2.  Testing should be easy:
1. Do a fresh calibration at a rotator angle of zero
2.  Run a guiding sequence and make sure things look right.
3.  Force NINA to change the rotator angle by a significant amount, like 45 degrees.
4.  Run another guiding sequence and see what happens
5.  If step 4 looks good, you're done.  If not, change the 'reverse' option in PHD2 and - this is important - go back to step 1 and repeat steps 1-4.

Good luck,
Bruce

Kevin Quin

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Jul 1, 2023, 1:32:50 PM7/1/23
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Hi Bruce.  NINA has an option to reverse, but it's tied to the Nitecrawler's ASCOM driver. If I set one to reverse, the other one will also set to reverse, and vice versa.  (NINA 2 uses polarity opposite to that used by most astronomy applications, something the developers are planning to fix in NINA 3.)  I need to leave reverse unchecked, or the rotator will never arrive at the right angle.  That's the case whether PHD2 has been started up or not.

Hopefully setting PHD2 to reverse the sign will solve this.  There might be some holes in the clouds tomorrow night to test this out.

Kevin

Kevin Quin

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Jul 7, 2023, 1:51:47 PM7/7/23
to Open PHD Guiding
Yes, that worked.  Rotation and guiding both work correctly now.

Bruce Waddington

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Jul 7, 2023, 2:11:18 PM7/7/23
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Good to hear you got it sorted out.

 

Have fun,

Bruce

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