Interstellar comet 3I/ATLAS was almost called 3I/Rubin, after researchers found that the giant survey telescope coincidentally spotted this visitor from the stars over a week before it was officially discovered.

Astronomers find interstellar comet 3I/ATLAS hiding in images taken before its official discovery

Source: space
Source Link: https://www.space.com/astronomy/comets/astronomers-find-interstellar-comet-3i-atlas-hiding-in-images-taken-before-its-official-discovery