[benfarahmand]

This is amazing! When taking long exposures like this over a significant amount of time, does anyone know how astronomers account for stellar parallax and/or the sun's orbit in the milky way? Are these factors too small to affect long exposure photos? And if they are too small to affect a long exposure photo, at what point does it become an issue?

[titzer]

Stellar parallax isn't a big effect. It wasn't even observable until the 1800s. Even the Hubble cannot measure parallax past about 10,000 lightyears, which is about 10% of the size of the Milky Way. For earth bound telescopes at this scale, it's totally negligible.