2003 EL61 (also written 2003 EL61) is a recently discovered, very large Kuiper belt object. Jose-Luis Ortiz, an astronomer at the Sierra Nevada Observatory in Spain, and colleagues discovered the object when they re-analysed observations they had made in 2003. They then scoured older archives and found the object in images dating back to 1955. Ortiz's group announced their discovery on July 29, 2005. A Caltech team led by Michael E. Brown had been observing the object for a year, but had not yet made the data public. Brown supported Ortiz and his group getting credit for the discovery.