ASIair, polar aligning and finding target.

[GrampyG]

 

I'm using ASIair Pro. 

1. How accurate should PA be? For example once 'smiley' shows is that good enough?

2. Once polar aligned I then go to my target. ASI does one plate solve, moves, then plate solves again and the target is centred. A video where the tutor moves the scope by the arrows on the software AFTER PA away from Polaris, plate solves then 'sync mount', then simply moves to the required target. Is this better practice? 

[StevieDvd]

If you do a good PA the first goto should be on target. If you have to move using the arrows and sync then your PA was not as good as you thought.

It also depends if you are viewing or imaging how good you do your PA. Viewing only needs a PA that lets you view long enough without needing constant manual corrections.

If you want short exposures without guiding then PA as good as you can, if guiding then it's still worth doing the best PA you can as it reduces the guiding corrections.

Ideally you'll get better at the PA part so you don't spend more time doing the PA than observing/imaging, and you'll find the level of PA that suits you.

 

 

[Scooot]

I’ve found after polar aligning, if I go to the home position, and polar align again it will be out again slightly. So I do this 3 or 4 times, tightening up a bit each time. I then get an alignment that remains fairly stable. I don’t know why this is necessary, maybe because of the time it takes to PA? Anyway this works well for me.

Ive also found that after going to a target, if I press the goto again it will platesolve again and tweak the mount to put the target nearer the centre. Again I might do this 2 or 3 times depending on how accurate I want it to be.

Edited February 18, 2022 by Scooot

[DougM43]

Once I have the smiley face I tend to stop there, to get it any better takes an absolute age of minuscule adjustments, 

guiding always seems consistent and stars always seem round so good enough for me, mine also plate solves again to centre the target on the chip, perfectly normal I think.

[iantaylor2uk]

If you're autoguiding, you only need to get polar alignment accurate to less than 5 mins. Once it is less than that I stop. 

[GrampyG]

Hi

Thank you for your replies. I tend simply to go for the 'smiley' - it seems to work for me. Also I have no problems going from the 'smiley' to the target, at least with a 740mm scope; after going there it seem only to make one correction to centre target

So I'll stick to what I have been doing. Thank you for your input and expertise.

G

[Elp]

I find after polar aligning tell the mount to go back to the home position (counterweight bar pointing down, telescope directly on top and in line with mount at +90 degree declination pointing directly at Polaris), this way you know if the "internal" alignment is correct. Often I've had plate solving slew attempts going further and further toward the ground (completely off) without having checked the home position at the beginning. Always good to send the scope back to home before slewing to another target. Good advice on the polar alignment here too, I've spent too much time trying to get to zero after getting into the ballpark (best was 4 arc seconds).