Re: PHD 2 Guiding "Good Enough"


Roland Christen
 

It looks like you have a fair amount of PE error which is contributing to that last remaining .5 arc sec of RA back and forth movement. You can determine the periodic error a number of ways, and of course you can use PEMPro to eliminate 90% of it. Have you ever run a simple PE curve to see where you are?

Rolando



-----Original Message-----
From: John Thompson via groups.io <jbtgolfer@...>
To: main@ap-gto.groups.io
Sent: Sat, May 2, 2020 10:30 am
Subject: [ap-gto] PHD 2 Guiding "Good Enough"

I know this is not a PHD 2 forum but I want to set reasonable expectations of my mount when guiding. Guiding can become an obsession and I want to know when to stop. I have a AP 1600 (no encoders) with a TEC 140 f/7 combined with a STF8300 main camera and an off-axis STi guide camera. I plan to install encoders this summer. I attached a screen shot that shows most of the relevant guiding info from PHD 2. My question is should I be happy with a .23 RMS and a +- .5 arc sec oscillation of the RA. The Dec looks stable and below .5 arc sec. The RA oscillation bothers me a little but perhaps it is "seeing" driven however this is a permanent observatory in a fairly dark site ( 21.6 SQM). I am getting reasonably round stars at 1200 second exposures. I have worked the polar alignment and drift pretty hard. Would appreciate hearing your thoughts or suggestions. I am also posting this to a PHD 2 forum.

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