Re: How Much RAPAS Misalignment is Too Much ?




Yes, use the push-pull screws to adjust the rear plate.    You can always restore the plate to flush and do it again.






George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...


From: <> On Behalf Of M Hambrick
Sent: Friday, September 24, 2021 11:11 AM
Subject: [ap-gto] How Much RAPAS Misalignment is Too Much ?


I have been getting a lot of what I suspect is field rotation in my guided images so I thought I would check my polar alignment using the RA Correction method as described in the manuals. I have a portable setup with an 1100 GTO mount that I set up and take down every night, and I set my polar alignment using the RAPAS. 

At the end of the RA Correction process I checked the position of Polaris in the RAPAS and compared it to what the Polar Align App said it should be. The results are in the sketches below.

I am assuming that if I am going to adjust the RAPAS, I will need to adjust the push pull screws in the plate at the base of the RA axis where the RAPAS attaches, but before I do this I wanted to make sure that this is not an irreversible process. I am worried that if I suddenly start adjusting the push-pull screws that I will do more harm than good.

Is the RA Correction procedure reliable enough that I should trust these results ? I think that at a minimum I will repeat the alignment procedure before I start adjusting anything.

The offset as seen seems in the sketches seems excessive, and I am also wondering what could cause the RAPAS alignment to get so far off, assuming that it was correct when I first got the mount. To my knowledge I have never dropped or damaged the RAPAS or the mount.

Any comments or advice would be appreciated.


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