|Object Type||Galaxy S0|
|Size||4.7' x 1.9'|
M 102 is an object that has not been unambiguously identified. In a letter written in 1783 to J. Bernoulli, Pierre Méchain (who discovered many of the latter objects in the Messier catalog) claimed that M 102 was actually an accidental duplication of M 101 in the catalog. As a result, this identification was widely accepted. However, more recent studies of the description given by Méchain, and the hand-written notes by Messier on his personal list of the Messier Catalog, indicate Méchain was incorrect in his letter as the galaxy NGC 5866 very closely matches those notes. As a result, many astronomers are inclined to disregard Méchain's letter and designate NGC 5866 as M 102.