Just a quick question.
After looking at the inside/outside diffraction patterns...they are compressed top right.
I also noticed a pic I took of NGC6744 showed coma in dim stars, same direction as compressed diffraction pattern.
So I need to collimate. I know I can use an artificial star (if I could get the distance between myself and the artificial star) but what about a Cheshire eyepiece or laser collimator or such like.
What's best, cheapest & easiest? I imagine a Cheshire?
