Combination of 30, 1 minute images unfiltered.
SBIG STL-1001E CCD. 20" f/6.8 Dall-Kirkham cassegrain telescope at prime focus.
| Object Type | Galaxy S0 |
| Constellation | Draco |
| Magnitude | 10.7 |
| 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.