Precovery

If you look for your new object after discovery, it's called "recovery". [...] if you find your new object in some old data that someone took before you discovered your object, it's called a "precovery".

Quaoar [...] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. It was discovered on June 4, 2002 by astronomers Chad Trujillo and Michael Brown at the California Institute of Technology [...] The earliest precovery turned out to be a May 25, 1954 plate from Palomar Observatory.