This is a presentation close to the original work and without much further discussion. For discussion of these observations see the Messier Catalog homepage.
(At the position Messier has given, no object is present which he could have seen, thus M91 was missing until 1969, when William C. Williams discovered that Messier had probably measured its position from M89, while he thought he used M58, and plotted it wrong.)
(Following the entry for M91 in the Connoissance des Temps for 1784,
Messier added the note below:)
`Note. The constellation of Virgo, & especially the northern Wing
is one of the constellations which encloses the most Nebulae: this Catalog
contains thirteen which have been determined: viz.
Nos. 49, 58,
59, 60,
61, 84,
85, 86, 87,
88, 89, 90, &
91.
All these nebulae appear to be without stars: one can see them only in a very
good sky, & near their meridian passage. Most of these nebulae have been
pointed to me by M. Méchain.'
(This notion is apparently the first impact of the Virgo cluster of galaxies into the scientific literature, i.e. the discovery of that galaxy cluster).
Last Modification: September 21, 2000