Hybrid Polar Scope-Drift Align Technique

[russellhq]

Polar alignment has always been a problem for me as I never had a clear view of Polaris nor did I have a clear view of the East or West horizons. I tried Alignmaster but could never get a clear view of the alignment stars. The only option left to me was to use either Astrotortilla's plate solving alignment or use PHD drift alignment and align the Azi axis and then position the scope as far East as I could (which was normally South East) and drift align the Alt axis.

But now, following the chopping down of a tree that was interfering with my house, I have a clear view of Polaris. And this got me thinking of a way to combine drift alignment and polar scope alignment. I've not tried this method out yet, but with precious little clear skies I thought it best to discuss it first in case there are any obvious pitfalls.

What I'm planning to do is to set-up my scope as normal and carry our a drift alignment of the Azi axis. Then, using the polar scope, adjust the Alt bolts so that Polaris sits on the reticule's circle. Assuming I adjust the Alt in the right direction and the polarscope is calibrated, then this should give me a pretty good PA in not too much time.

[dark knight]

hmmm, not sure how this would work out as Drift Alignment relies on very fine adjustment of both Az and Alt constantly moving between the two a few times , as each adjustment has an effect on the other,, you may find what accuracy you achieve in drifting in Az will then be undone by using the polarscope for Alt, as this will have an effect on your Az and you will end up chasing accuracy, I could be wrong though.... I see you use EQMod, why not just use it's simple inbuilt polar alignment tool, would be much quicker and accurate enough for astrophotograghy

[russellhq]

Thanks Carl, I also plan on using EQMODs polar align tool (I was watching Chris's video on Youtube yesterday). I had assumed though that if I combine the 2 methods, I may get better accuracy.

Also, I'd not read about the iterative process you mentioned. I had assumed that once I had set the Azi then setting Alt had no effect on Azi (assuming the mount was level).

[dark knight]

when drift aligning there is a definite relationship between the Alt and Az adjustments, each one slightly altering the other, that's why it takes so much time to do as you have to keep switching between adjusting Alt and Az until it is fine tuned enough for your needs.