Messier 38

Discovered by Giovanni Batista Hodierna before 1654.
Independently rediscovered by Le Gentil in 1749.

Messier: M38.

September 25, 1764. 38. 5h 12m 41s (78d 10' 12") +36d 11' 51"
Cluster of small stars in Auriga, near the star Sigma, little distant from the two preceding clusters [M36 and M37]; this one is of square shape & contains no nebulosity, if one takes care to examine it with a good telescope. Its extension is about 15' of arc. (diam. 15')

[Mem. Acad. for 1771, p. 449-450 (first Messier catalog)]
In the night of September 25 to 26, 1764, I have discovered a cluster of small stars in Auriga, near the star Sigma of that constellation, little distant from the two preceding clusters: this one is of square shape, & doesn't contain any nebulosity, if one examines it with a good instrument: its extension may be 15 minutes of arc. I have determined its position: its right ascension was 78d 10' 12", & its declination 36d 11' 51" north.
[p. 458] 1764.Sep.25. RA: 78.10.12, Dec: 36.11.51.B, Diam: 0.15. Cluster of small stars, near the star Sigma Aurigae, & little distant from the two preceding clusters [M36 and M37].

Bode: Bode 9.

A star cluster.

Koehler: Koehler No. 38

Above w in Auriga.

Caroline Herschel

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

William Herschel

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 654]
1805, Nov. 23, Review. Large 10 feet reflector. A cluster of scattered, pretty large [bright] stars of various magnitudes, of an irregular figure. It is in the Milky Way.

Smyth: CCIV [204]. M38.

CCIV. 38 M. Aurigae.
AR 5h 18m 41s, Dec N 35d 44'.9
Mean Epoch of Observation: 1835.80 [October 1835]
Position 251d.0 (w 1), Difference AR 14".5 (w 1)
A rich cluster of minute stars, on the Waggoner's left thigh, of which a remarkable pair in the following are here estimated. A [mag] 7, yellow; and B 9, pale yellow; having a little companion about 25" off in the sf [south following, SE] quarter. Messier discovered this in 1764, and described it as "a mass of stars of a square form without any nebulosity, extending to about 15' of a degree;" but it is singular that the palpable cruciform shape of the most clustering part did not attract his notice. It is an oblique cross, with a pair of large [bright] stars in each arm, and a conspicuous single one at the centre; the whole followed by a bright individual of the 7th magnitude.
The very unusual shape of this cluster, recalls the sagacity of Sir William Herschel's speculations upon the subject, and very much favours the idea of an attractive power lodged in the brightest part. For although the form be not globular, it is plainly to be seen that there is a tendency toward sphericity, by the swell of the dimensions as they draw near the most luminous place, denoting, as it were, a stream, or tide, of stars, setting toward the centre. As the stars in the same nebula must be very mearly all at the same relative distance from us, and they appear to be about the same size [brightness], Sir William infers that their real magnitudes must be nearly equal. Granting, therefore, that these nebulae and clusters of stars are formed by their mutual attraction, he concludes that we may judge of their relative age, by the disposition of their component parts, those being the oldest which are the most compressed.
To fish up this object, a line from Rigel mist be carried northwards through Beta Tauri, on the tip of the Bull's left horn, and about 7deg beyond, where it will be intersected by the ray from Capella to Betelgeuze [sic].

John Herschel, General Catalogue: GC 1119.

GC 1119 = M38.
RA 5h 19m 17.0s, NPD 54d 17' 36.1" (1860.0) [Right Ascension and North Polar Distance]
Cl; B; vL; vRi; iF; st L & S. 7 observations by W. & J. Herschel.
Cluster; bright; very large; very rich; irregular figure [shape]; large & small [bright and faint] stars.

Dreyer: NGC 1912.

NGC 1912 = GC 1119; M 38.
RA 5h 19m 17s, NPD 54d 17.6' (1860.0) [Right Ascension and North Polar Distance]
Cl, B, vL, vRi, iF, st L & S; = M38
Cluster, bright, very large, very rich, irregular figure [shape], large & small [bright and faint] stars.