Thread: Gemini PAC bug
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Old 13-11-2007, 09:46 PM
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Lee
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Join Date: Sep 2005
Location: Newcastle, Australia
Posts: 2,414
Gemini PAC bug

This topic might be getting a bit old.... but .....

I have worked out that my Gemini (and maybe all of this version) has a definite PAC bug (polar axis correction). It issues elevation corrections the wrong way. Azimuth seems fine - elevation is definitely reversed.

Here's what I did.

Built a model (5 stars each side meridian, all separated by at least 2hr RA).
A=-7, E=7

Did a PAC on SAO128085 (nearest star to intersection of meridian/equator) - adjusted so as to only correct the error by about half.

Built same model again-
A=-3, E=13 A has improved, E not so.....

I did PAC on the same star - but this time, did not touch azimuth knob, and pushed the star further away from the centre with the elevation knob, instead of correcting it.....

Built same model -
A=-3, E=4 - what the?

Did another elevation-in-reverse PAC, but did make some azimuth adjustment in the correct direction....

Built same model -
A=-2, E=3

Same again.....
A=-1, E=-1

I think Gemini is up to Level 4, V1.04 nor - this unit is a V1.01.... If anyone else would try it, that might be cool..... if PAC worked well, I think it would be a huge time saver for people especially with non-permanent setups....
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