Greetings, Satellites
Gifted with a 'surprise' clear sky last night, I decided to set the scope up for some shots of Messier 101: The Pinwheel Galaxy. I was going over the images taken and was surprised to see in one of the five-minute images had been ruined not by one passing satellite but by two. They make a neat crisscross in the image, almost as if nearly missing collision while speeding through their earthly orbits. I opened my planetarium software Stellarium to see if I could identify the two photo-bombers and thought I’d share a little bit of what I found out. In a 300-second exposure, a lot can happen to muck up your data. From poor star tracking, passing clouds, satellites, airplanes and even meteors: If these near-earth occurrences were not your primary target, they end up leaving nasty marks on your image as they skirt by uninvited. Since faint deep sky objects require a lot of images to make out faint detail, most of these marks are outliers in the ov