sharpcap polar alignment difference

[iwols]

hi all just using sharpcap to polar align but seem to get slightly different results on a rerun,can be anything from good to poor,fighting the weather and poor arrangement for adjustment on my otherwise good heq5 mount,but is this normal,and how good is good enough,even though i can have a good alignment followed by a report of poor after a rerun,im using a fixed mount cheers

[RolandKol]

It probably depends on seeing and the exposures used...

The longer, the better, - as longer exposures will equalize atmospheric disturbances,

but will make all adjustments more difficult, so you must pick up not a Very short exposures initially, - and make them longer during a final PA test/re-run.

I also use SharpCap for PA, but consider it as initial/rough alignment, once done,  I also always run PHD2 drift alignment and my PA error was never close to 1 arc-min after SharpCap.

I usually finalize PA using PHD2 drift alignment tool, PA error to be somewhere a bit less than 1 arc-min, - it is enough for me as I am imaging at 1.33" per pixel with exposures up to 300sec, my usual guiding ends up at around 0.7 Total RMS.

P.S.

Forgot to mention, even if PHD2 Drift Alignment is done in a manner I wrote.

Later, PHD Guiding Assistant, usually shows PA error around  1 - 2.5 arc-min in 300 sec testing period.

P.P.S

it does not mean I do all correctly, - just sharing my results

[david_taurus83]

I use the Polemaster camera on the RA axis but Sharpcap for the polar align routine. I can get it down to excellent after adjustments but when I return the mount to home it usually gives a different result. If I slew to the opposite side and check it's different again! So what your experiencing is normal. I don't get hung up on it. I adjust on one side  and crack on. Try guiding and see how it goes.

 

EDIT: Just read your on a fixed mount. If permanent then I agree with the above comment. Use Sharpcap for initial alignment and prob worth putting the time in to drift aligning for a better result.