This elliptical galaxy is a satellite of the much larger spiral
galaxy M 31. Messier noticed this galaxy, even sketching it, but
never included it in his list of objects. It was finally added,
as the last item in the accepted "Messier" list, in 1966. Because
it is much smaller than most elliptical galaxies, and because it
displays some dark markings that look like dust lanes (which elliptical
galaxies generally do not have), this galaxy is sometimes categorized
as a "dwarf spherical" galaxy.

Image data:
Camera: Canon 350 XT (modified)
Exposure: ISO 800, 5 minutes x 24
Telescope: William Optics 66mm refractor, 0.8x reducer and field flattener
(cropped from original image)