Polar alignment and autoguiding?

[ollypenrice]

I find this a very interesting topic because I am never sure exactly how accurate PA should be.  In fact I believe I have read on this forum that a slight out of alignment can in certain circumstances actually produce better guiding.

Chris

This can be the case when a mount has backlash in Dec. You set it to correct in only one direction, the one needed to correct the polar misalignment. (Identify which direction by trial and error and reverse after the flip.) All that happens is that you avoid setting up a vicious circle of guide impulses rocking the scope back and forth across the backlash in Dec. It's not unlike running a tad east-heavy in RA balance.

I've said this before but round stars are not an indication of excellent guiding. Oval ones do indicate a guiding problem but truly random errors lose resolution yet give round stars. The finer your pixel scale the more this matters.

Olly

[robmichael81]

Why don't you use the software that you already have on the handset? It works very well. So, do a single 2 star alignment on the same side of the meridian as your imaging target. Then run the polar alignment routine on the handset as described in the manual. Repeat until your PA is at or below 30 arc seconds and you will be fine. If you really want to go more accurate just run the drift alignment routine in PHD2. This process will keep your set up time to a sensible period. No need for a polar scope.

Will give that a go Chris, in all honesty I am not getting on with using the polar scope for alignment any way so this seems like the perfect answer.

Cheers