Messier 37

Discovered by Giovanni Batista Hodierna before 1654.
Independently rediscovered by Charles Messier on September 2, 1764.

Messier: M37.

September 2, 1764. 37. 5h 37m 01s (84d 15' 12") +32d 11' 51"
Cluster of small stars, little remote from the preceding [M36], above the parallel of chi Aurigae; the stars are smaller, more close together and enclosing some nebulosity; with an ordinary telescope of 3.5 feet [FL], one has pain to see the stars: this cluster is reported on the Chart of the second Comet of 1771, Mem. Acad. 1777. (diam. 9')

[Handwritten remark in Messier's copy:] Seen again 6th March [?], 1781.

[Mem. Acad. for 1771, p. 449 (first Messier catalog)]
In the same night [September 2 to 3, 1764], I have observed a second cluster of small stars which were not very distant from the preceding, near the right leg of Auriga & on the parallel of the star Chi of that constellaiton: the stars there are smaller than that of the preceding cluster: they are also closer to each other, & contain a nebulosity. With an ordinary [non-achromatic] refractor of 3 feet & a half, one has difficulty to see these stars; but one distinguishes them with an instrument of greater effectivity. I have determined the position fo this cluster, which may have an extension of 8 to 9 minutes of arc: its right ascension was 84d 15' 12", & its declination 32d 11' 51" north.
[p. 457] 1764.Sep. 2. RA: 84.15.12, Dec: 32.11.51.B, Diam: 0. 9. Cluster of small stars, little distant from the preceding [M36], & on the parallel of the star Chi Aurigae.

Bode: Bode 13.

A nebula.
On November 2 [1774], I discovered in Auriga, west and below the star Theta, a new nebulous star, which, observed through the 7-foot telescope, appeared as a vivid nebulous patch, in which no stars were recognizable, of uneven shape and slightly elongated in the north-south direction. Its distance from the star Theta is 4deg 58' end from Nu 4deg 53'. Mr. Le Gentil has discovered two new nebulous stars in Auriga (M36 and M38), which appear to the East of the previous as small clusters through telescopes. Around the new nebula there appeared many small stars in the 7-foot telescope, and chiefly it is situated in a position with the three brightest as shown in the 7th figure, where also the measured separations are shown.

Caroline Herschel

October 13, 1782. Observed "a nebula below Phi Aurigae." This may be M37, M36, or M38.
October 29, 1782. Observed M37 and M13.

William Herschel:

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 653-654]
1782, Nov. 4. Is an astonishing number of small stars with 227; they are almost all of the 2ndor 3rd class. I see no kind of nebulosity in the spot. With 460 the whole is resolvable into stars without nebulosity.
1783, August 24. A useful, coarse step; it will serve to learn to see nebulae, because it contains many small stars mixed with others in various magnitudes, many of which are not to be seen without great and long attention.

John Herschel (1833): h 369.

h 369 = M37.
Sweep 52 (January 23, 1827)
RA 5h 41m 8.2s, NPD 57d 30' 56" (1830.0) [Right Ascension and North Polar Distance]
v fine L cl, all resolved into st 10...13 m. It fills 1 1/2 field, but the straggling stars extend very far. There may be 500 stars.
Very fine large cluster, all resolved into stars of 10th to 13th magnitude. It fills 1 1/2 field, but the straggling stars extend very far. There may be 500 stars.

Sweep 51 (January 22, 1827)
RA 5h 41m 10.3s, NPD 57d 29' 54" (1830.0)
Splendid cl st 11...15 m; no unresolved neb; p comp but not m b M; fills field.
Splendid cluster of stars of 11th to 15th magnitude; no unresolved nebulosity; pretty compressed but not much brighter toward the middle; fills field.

Sweep 56 (January 27, 1827)
RA 5h 41m 10.8s, NPD 57d 30' 20" (1830.0)
Irregular; not very rich; fills field.

Smyth: CCXXX [230]. M37.

CCXXX. 37 M. Aurigae.
AR 5h 41m 46s, Dec N 32d 30'.1
Mean Epoch of Observation: 1836.79 [October 1836]
Position 357d.0 (w 1), Distance 25".0 (w 1)
A double star in a cluster in front of Auriga's left shin. A and B, both 10th-magnitude, and pale yellow. A magnificient object, the whole field being strewed as it were with sparkling gold-dust; and the group is resolvable into about 500 stars, from the 10th to the 14th magnitudes, besides the outliers. It was found and fixed by Messier in 1764, who described it as "a mass of small stars, much enveloped in nebulous matter." This nebulous matter, however, yields to my telescope, and resolves into infinitely minute points of lucid light, among the distinct little individuals. It is immediately preceded on the parallel by another small double star: and is about half a degree north east of 225 P. v., whose alineation is already described [No. CCXXVIII (228) in Smyth's list].

John Herschel, General Catalogue: GC 1295.

GC 1295 = h 369 = M37.
RA 5h 43m 7.5s, NPD 57d 29' 38.3" (1860.0) [Right Ascension and North Polar Distance]
Cl; Ri; pCM; st L & S. 8 observations by W. & J. Herschel.
Cluster; rich; pretty compressed toward the middle; large & small [bright and faint] stars.

Dreyer: NGC 2099.

NGC 2099 = GC 1295 = h 369; M 37.
RA 5h 43m 8s, NPD 57d 29.6' (1860.0) [Right Ascension and North Polar Distance]
Cl, Ri, pCM, st L & S; = M37
Cluster, rich, pretty compressed toward the middle, large & small [bright and faint] stars.
Remark: Figure in O. Lohse [A.N. cxv].