a combination of things, the distances you're looking at are mind-numbingly huge. you might think it's a long way to the chemist but that's just peanuts to spa

a combination of things, the distances you're looking at are mind-numbingly huge. you might think it's a long way to the chemist but that's just peanuts to space. This means that even though things are moving, and fast, they still look like they're in the same place from this far away. Along with that, the images aren't a single exposure over years, but days at a time at worst. that means that any minor movement can be adjusted for when combining the images for the final result.