Astronomy is like being in a dark room and looking for a black cat by analyzing the raw image data of several insanely sensitive cameras, then finding out what the cat looks like, what it looked like right after birth, where it'll be next year and what its gut microbiome consists of, based on a slight reddish hue in its fur.

Alternatively: Astronomy is like being in a dark room and saying "Something seems off. There must be a black cat in here."