Re: RAPAS on Mach2

Terri Zittritsch

For those that followed this and might be considering a polemaster, and noted that I wasn't getting the result I expected, I think I've figured out why I was seeing such a poor result.     When I started using the polemaster, it was with my Atlas mounts, and given I always need to do guiding, I didn't much worry about whether I was exactly on the pole or not, and didn't bother with drift measurements.. and guiding seemed to work just fine.   And as I recall, I was always on the 2nd step for both gain and exposure time.    Fast forward to getting the Mach2.  Now I'm trying to evaluate the performance of the Mach2, so wanting to do a more accurate polar alignment, and get it done early in the evening.   So I moved to the lowest setting on gain and exposure time (screen becomes viewable earlier).. I could always see the stars, but they were dimmer and smaller, and my thinking is that smaller is better for more accurate alignment.     But, for last step, the fine adjustment monitor step (going from 5-6 arc min alignment to 30" alignment) Polemaster actually picks up some other dimmer stars..   I believe when I decreased my gain and exposure times, these stars weren't being picked up reliably in the monitor step.  
To cut off the story,I think I was basically staying at the 5-6 arc minute gross polar alignment, which is essentially what I was measuring in PHD2.   After thinking about it, I decided to go back to the higher gain and exposure time to see if it made a difference.     This past weekend, I upped the gain and exposure time on the camera, did my polar alignment, and I noted that the monitor step adjustment required more tweaking than it had needed in prior mach2 polar alignments.     In checking my drift in PHD2... I had essentially zero.   Curve jumping around due to atmosphere, but no trend whatsoever over at least 5 minutes.   

So for anyone else who's had trouble getting better than the advertised gross polar alignment on the polemaster, this could be your issue.


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