Probably discovered by Hodierna before 1654.
Independently discovered by Charles Messier on August 25, 1764.
[Mem. Acad. for 1771, p. 448 (first Messier catalog)]
In the night of August 25 to 26, 1764, I have discovered a nebula between the head of the northern Fish [of Pisces] & the large Triangle [Triangulum], a bit distant from a star whioch had not been known, of sixth magnitude, of which I have determined the position; the right ascension of that star was 22d 7' 13", & its declination 29d 54' 10" north: near that star, there is another one which is the first of Triangulum, described by the letter b. Flamsteed described it in his catalog, of sixth magnitude; it is less beautiful than that of which I have given the position, & one should set it to the rank of the stars of the eighth class [magnitude]. The nebula is a whitish light of 15 minutes in diameter, of an almost even density, despite a bit more luminous at two third of its diameter; it doesn't contain any star: one sees it with difficulty with an ordinary [non-achromatic] refractor of one foot [FL]. I have compared it to the star Alpha Trianguli, & with that of which I have reported the position. I have found the right ascension of that nebula at 20d 9' 17", & its declination of 29d 32' 25" north.
[p. 457] 1764.Aug.25. RA: 20. 9.17, Dec: 29.32.25.B, Diam: 0.15. Nebula without stars, between the head of the northern Fish [of Pisces] & the great Triangle, it has little distance from a new star of 6th magnitude & the star b Trianguli, according to Flamsteed.
[PT 1800 p. 78-79. Reprinted in:
Scientific Papers, Vol. 2, p. 48]
August 24, 1783. I viewed the nebula north preceding Flamsteed's 1 Trianguli, discovered by Mr. Messier, in 1764 [M 33 = NGC 598].
"7-feet reflector; power 57. There is a suspicion that the nebula consists of exceedingly small stars. With this low power it has a nebulous appearance; and it vanishes when I pus on the higher magnifying powers of 278 and 460."
Oct. 28, 1794. I viewed the same nebula with a 7-feet reflector.
"It is large, but very faint. With 120, it seems to be composed of stars, and I think I see several of them; but it will bear no magnifying power."
[PT 1818, p. 442-443. Reprinted in:
Scientific Papers, Vol. 2, p. 598]
The 33rd of the Connoissance. [M 33 = NGC 598]
"1799, 10 feet finder. It is visible as a faint nebula."
"1783, 1794, 7 feet telescope. With 75, it has a nebulous appearance; it will not bear 278 and 460, but with 120 it seems to be composed of stars."
"1799, 1810, 10 feet telescope. The brightest part is resolvable; some of the stars are visible."
"1805, 1810, Large 10 feet telescope. The condensation of the stars is very gradually towards the middle; but with the four powers 71, 108, 171, and 220, some nebulosity remains. The stars of the cluster are the smallest points imaginable. The diameter is nearly 18 minutes."
The profindity of this cluster, by the observation of the 10 inch telescope, must be of the 344th order.
[Unpublished Observations of Messier's Nebulae and Clusters.
Scientific Papers, Vol. 2, p. 653]
See above pp. 48 and 598. Two observations are recorded as being of V.17, the outlying parts of the great nebula; they were made September 11 and 12, 1784, and described in vol. i. [SP1] pp. 255-256.
Last Modification: March 25, 2005