Re: Fine tuning PHD2 settings for 1100 with Encoders #Guiding

Roland Christen

First I would let the mount track and record the tracking graph with corrections turned off. That will give you a baseline of the amount of natural sky scintillation (or seeing) that your site is experiencing. You cannot guide out seeing, so that will be the best you can do on that particular night. It depends on where your setup is located, of course - the further north and near the leeward side of mountains, the worse the seeing. The further south you are, and closer to the Gulf, the steadier the seeing will be.
You need to establish a baseline so that you don't have any unrealistic expectations about achieving a certain rms guiding error. Watching the Dec axis fluctuations over a 5 minute period is the best way to see that because the Dec motor will be sitting exactly still and any fluctuations or P-P value will be caused only by the atmosphere above. Of course you don't want to do this with the model running, and also you want to disregard any drift due to polar misalignment, atmospheric refraction, etc.

Set a 10 second "time lapse" between exposures
Second, I would cut my guide exposure to between 2 and 3 seconds and drop the 10 second delay down to 2 to 3 seconds.


-----Original Message-----
From: Andrew J <andjones132@...>
Sent: Fri, Oct 8, 2021 3:25 pm
Subject: [ap-gto] Fine tuning PHD2 settings for 1100 with Encoders #Guiding

We finally got a clear night and I was finally able to create a pointing model and attempt my first imaging run last night with my 1100GTO-AEL. I created about a 200 point model and setup PHD2 following some helpful advice from Brian Valente here on this forum back in July.
Here are my settings:
  • Used Guiding Assistant to set the RA/DEC MinMo by letting it run for about 5 mins
  • Set sidereal guide rate to 1x
  • Use 4 second guiding exposures
  • Set a 10 second "time lapse" between exposures
  • Use lowpass 2 algorithm on both RA and DEC
  • Set Medium aggressiveness (I used 65 for RA and 80 for DEC)
  • Don’t use backlash compensation

Although my guiding was much better than I ever got with my Mach1, I still think there might be some room for improvement. Here is the graph that I had at the end of the session that was fairly representative of what I saw earlier in the night. I tried fumbling with the MinMo and Aggressive settings to try and smooth it out a bit, but was unable to get a better result. I would welcome any recommendation on how I can improve my settings or things to try.
Thanks in the advance for the help

Andrew J

Roland Christen

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