Chris, you\'re using an A7r1? If you don\'t see stars for focusing make sure you have it set to bulb, f2.8, 6400 iso, turn lens to infinity mark, set live view to first 5x) magnification setting, then point and pan around to the brightest star or planet you see. It should show up.
The purple noise are deep blacks being read incorrectly due to high iso, compounded by vignetting in the corners. Hence a reason for foreground twilight shot at low iso, then pp for nighttime look.
I read that simply set their infinity mark on the lens during the daytime. With temp changes and maybe little nudges on the focus ring, I can\'t say you\'d have perfect focus. I\'m sure it\'s close though. If you had a Bahtinov mask that WORKED with your lens, you\'d know for sure.
