M-73 (NGC 6994), M-40, M-91 and M-102

M-73 is not one of the most spectacular clusters for the six-inch scope. Indeed, it is only an accidental grouping of four stars in Aquarius. This object belongs to a class called "Doubtful Listings", and three other Messier objects belong to this class.

M-40 is only a double star. M-102 is probably a repetition of M-101. M-91 is simply non-existent. (My own suggestion is that it may have been, ironically, a comet.) In any case it is probably unwise to spend a great deal of time admiring these objects.

[NOTE: The Students for the Exploration and Development of Space (SEDS) Messier Database lists M-91 as NGC 4548, a galaxy in Coma Berenices. Apparently, there is no clear consensus as to the identity of M-91.]

NGC: 6994
OTHER NAMES: M-73
CLASS: asterism
NUMBER OF STARS: 4
POSITION: 20h 56m -12d 50'
CONSTELLATION: Aquarius
DATE OF SKETCH: 10/04/75
MAGNIFICATION USED: 70x, 140x