[Atmos (Colin)]

Originally Posted by AndrewJ

Gday Colin
If its only aligning you want to do, then you will be using relatively bright stars.
As such, just badly defocus until you get a large donut that fills say 1/2 to 3/4 the fov. You can easily centre this as your eye brain can detect any offsets much easier than a point source in the middle.
If you are using multiple stars, dont change focus till done and it will remove any minor focus shift errors.

Andrew