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PHD2 settings

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#1 Borodog

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Posted 03 December 2021 - 12:24 PM

Hi all. PHD2 seems to be working fairly well for me, but for long exposures my stars are a little eggy in the RA direction. My RA error runs about twice my DEC error. What settings should I look at to improve this? FWIW it's a C8 on a CGEM, well leveled, balanced, and polar aligned (< 1'). Multi-star guiding, 2s exposures. No errors reported during PHD2 calibration. Guide scope is well focused, darks used. Unfortunately I forgot to take a screen shot while guiding last night, but everything looked reasonable, other than the RA error (~0.2 pixels last night, ~1") being twice the DEC error (~0.1 pixels, ~0.5"). No wind to speak of. Other than turning on multi-star guiding, all my PHD2 settings are the defaults.

 

If there is a good tutorial online that explains how to use the settings to address specific problems like mine, I would greatly appreciate that, too.

 

Thanks for your time and thoughts.

 



#2 Boeglewatcher

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Posted 03 December 2021 - 12:49 PM

Can you post the guide log, please?

in general, RA RMS is usually a bit higher than DEC RMS. But need to look at your guide log.

there is a best practice pdf available on the phd2 website.

cs Joachim 


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#3 michael8554

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Posted 03 December 2021 - 12:50 PM

Post a GuideLog from the PHD2 folder that includes Cal.


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#4 bobzeq25

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Posted 03 December 2021 - 01:42 PM

Almost all of us have more RA error than DEC.  Polar align good enough, and DEC almost guides itself.

 

Settings I've found useful.

 

Multistar guiding.  Nothing made anywhere near as much difference.

 

The PPEC algorithm.

 

Following the advice from guiding assistant, although backlash compensation only works sometimes.

 

The defaults are pretty good, otherwise.  Don't crank up the aggression, or shorten the exposure too much.


Edited by bobzeq25, 03 December 2021 - 01:44 PM.

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#5 Borodog

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Posted 03 December 2021 - 02:09 PM

Almost all of us have more RA error than DEC.  Polar align good enough, and DEC almost guides itself.

 

Settings I've found useful.

 

Multistar guiding.  Nothing made anywhere near as much difference.

 

The PPEC algorithm.

 

Following the advice from guiding assistant, although backlash compensation only works sometimes.

 

The defaults are pretty good, otherwise.  Don't crank up the aggression, or shorten the exposure too much.

 

Thank you, Bob. This is exactly what I was looking for, and gave me exactly the terms I needed to search on to find the right parts of the documentation.

 


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