Messier 102

Its original discoverer Pierre Méchain retracted his discovery two years after publication and said that it was a duplicate observation of Messier 101.

Because Messier was only interested in finding comets, he created this list of non-comet objects that frustrated his hunt for them.

M102 was observed by Méchain in late March or early April 1781 and was added by Messier to the final version of his catalogue published in 1781.

His description of the object was the following: Nébuleuse entre les étoiles Omicron du Bouvier & Iota du Dragon: elle est très-foible; près d'elle est une étoile de la sixième grandeur.

In a letter written in 1783 to J. Bernoulli, Pierre Méchain (who had shared information about his discoveries with Messier) claimed that M102 was actually an accidental duplication of M101 in the catalog.

Messier 101 as observed by the Hubble Space Telescope . Credit: NASA / ESA .
NGC 5866 as observed by the Hubble Space Telescope . Credit: NASA / ESA .