Messier 102

Discovered probably in March or April 1781 by Pierre Méchain, or little later in 1781 by Charles Messier.
Independently discovered by William Herschel on May 5, 1788.

Messier: M102.

[March 1781]. 102.
(Méchain) "Nebula between the stars Omicron [actually Theta] Bootis & Iota Draconis: it is very faint; near it is a star of the sixth magnitude."

(Handwritten position added by Messier in his personal copy: 14h 40m, +56.)

(The discoverer, Pierre Méchain, disclaimed the discovery of this object in his letter to Bernoulli, written May 6, 1783, and declared it was an erroneous reobservation of M101. However, his description matches well with an existing object, NGC 5866, as may Messier's position measurement, if one takes an error of exactly 5 degrees in right ascension into account. This issue was ever since, and is still, subject to controversial discussion. Anyway, M102 was missed for more than a century.)