APPM - offset when telescope is powered off and then powered on a day or later #APCC


Dan R Price
 

I am having a minor problem with APCC/APPM.  I begin with running APPM for about 30 points, all near the DEC of my target for the evening.  This works just fine.  Once APPM is done I run TheSkyX, find my target, switch over to SGP and run the imaging sequence for several hours.  This works just fine.  I then park the Mach2GTO and power off everything (telescope, computer).  I am very careful not to touch the telescope or mount.  The next evening I power everything up and assume I am good to go.  I run TheSkyX, find my target and slew to it.  I then take a simple image to check location and always find I have an offset of roughly 10 arc minutes from my location the night before.  I then go to APPM and do a Verify for a couple of points.  The Verify says I am .1 arc minutes or better.  At this point I abort the Verify.  I then go back to TheSkyX, do a find on my target and slew to it again.  This time the target position is almost perfect.  The rest of the evening goes smoothly.  My question is - what am I misunderstanding about APPM (or TheSkyX) that requires I run APPM/Verify on a couple of points in order to get the kind of accuracy in pointing I had the night (or several days) before?  I think the same thing happens if I use the APCC GOTO instead of TheSkyX, but I have only tried this once and was not careful in testing it.  - Dan Price 

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