Re: Spurious guider move command?

Roland Christen

I think I know why your guide errors are what they are. I believe your guide camera (and probably your imaging camera) is oriented at an angle to the RA. Check your parameter number for the angle. If it is not either 0 or 180 or thereabouts, then you will not get any correlation between the guider correction numbers and the error numbers in your guider log. It is always best to orient the guide camera so that the X and Y axes line up with RA/Dec.

-----Original Message-----
From: Lloyd Smith sixburg@... [ap-gto]
To: ap-gto
Sent: Tue, Aug 11, 2015 7:42 am
Subject: [ap-gto] Re: Spurious guider move command?

John D…
Your photo is very similar to mine with the exception of the direction of the star trail error.  I need to confirm whether or not the movement is only in RA.  The mount is purposely imbalanced a bit as Roland suggests.  I’m doubtful of wind being the issue in my case as wind is monitored by two different instruments and in the logs there are no winds over 3 mph during the capture of the “ruined” subs.  Over the course of a night perhaps 1 maybe 2 subs are ruined.  Contrary to the implications in other posts I do have a clue as to what I’m doing and have 3 other very similar A-P based systems in the same remote observatory all operating flawlessly except this one (only differences are the OTA and camera) All other systems are on non-A-P mounts and have never shown this behavior.  Ergo, my first hypothesis focused on the mount (i.e, gear mesh), but that didn’t fix it.   I’m going to test with another guider.  It seems to me a spurious signal from the guider could be a cause. 

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