Right Ascension	11 : 20.2 (h:m)
Declination	+12 : 59 (deg:m)
Distance	35000 (kly)
Visual Brightness	8.9 (mag)
Apparent Dimension	8x2.5 (arc min)
Discovered by	Pierre Mechain      1780

M66, together with its neighbors M65 and NGC 3628, forms a most conspicuous triplet of galaxies, the Leo Triplett or M66 group, located at a distance of about 35 million light years.

M66 is considerably larger than its neighbor, M65, and has a well developed but not well defined central bulge, and is therefore classified Sb. Obviously its spiral arms are deformed, probably because of the encounters with its neighbors. They seem to be distorted and displaced above the plane of the galaxy. Note how one of the spiral arms seems to pass over the left side of the central bulge. Much dust is visible here, as well as a few pink nebulae, signs of star formation, near the end of one of the arms.

This image was obtained by David Malin with the Anglo Australian Telescope, and is copyrighted. 

Three supernovae have appeared in this galaxy:

	1973R which was of type II and reached mag 15 was found on Dec 12, 1973.
	1989B was discovered on Jan 31, 1989 and became as bright as mag 12.2 on Feb 1, 1989.
	1997bs was discovered by the Lick Observatory Supernova Search Team as it occurred on April 15, 1997 at 13" west, 67" south of the galaxy's center and reached mag 17.0; this was of peculiar type IIn.

Halton Arp has included M66 in his Catalogue of Peculiar Galaxies as entry No. 16. Moreover, he assigned the number 317 to the Leo Triplett (M66 together with M65 and NGC 3628).

Messier observed M66 on March 1st, 1780 "Nebula discovered in Leo; very faint and very close to the preceding one(M65)."Charles Messier from his catalogue