Messier 46

Discovered by Charles Messier on February 19, 1771.

Messier: M46.

February 19, 1771. 46. 7h 31m 11s (112d 47' 43") -14d 19' 07"
"A cluster of very small stars, between the head of the Great Dog and the two hind feet of the Unicorn, [its position] determined by comparing this cluster with the star 2 Navis, of 6th-magnitude, according to Flamsteed; one cannot see these stars but with a good refractor; the cluster contains a bit of nebulosity."

Caroline Herschel: No. 3

No. 3.
March 4th, [17]83. 1 deg S following the nebula near the 2nd Navis [Puppis; M47], a Nebula the figure is done by memory. My Brother observed it with 227 and found it to be, an astonishing number of stars. it is not in Mess. catalogue.
November 19 [1783]. My 3d nebula is Mess. 46.

William Herschel

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 657]
1786, Mar. 19 (Sw. 540). A beautiful, very rich, compressed cluster of stars of various magnitudes.

H IV.39 [NGC 2438]

John Herschel (1833): h 463.

h 463 = M46.
Sweep 111 (December 16, 1827)
RA 7h 34m 1.6s, NPD 104d 25' 45" (1830.0) [Right Ascension and North Polar Distance]
The brightest part of a v fine rich cl; stars = 10m; which fills the field. Within the cl at its n edge is a fine planetary neb.
The brightest part of a very fine rich cluster; stars of 10th magnitude; which fills the field. Within the cluster at its northern edge is a fine planetary nebula.

h 464.
h 464 = H IV.39.
Sweep 111 (December 16, 1827)
RA 7h 34m 1.6s, NPD 104d 20' 25" (1830.0)
A planetary neb 3s.75 (time) in diam. Exactly R of a F equable light. Has a v minute * n l n of centre. It is not b M nor fading away, but a little velvety at the edges. At the n edge of the fine cl M46.
A planetary nebula 3.75 s (time) in diameter. Exactly round of a faint equable light. Has a very minute star north l n of centre. It is not brighter to the middle nor fading away, but a little velvety at the edges. At the northern edge of the fine cluster M46.

Smyth: CCCII [302]. M46.

CCCII. 46 M. Argo Navis [now Puppis].
AR 7h 34m 30s, Dec S 14d 27'.3
Mean Epoch of Observation: 1836.24 [March 1836]
Position 90d.0 (w 1), Distance 15".0 (w 1)
A very delicate double star in a fine cluster, outlying the Galaxy, over Argo's poop. A 8 1/2 [mag], and B 11, both pale white.A noble though rather loose assemblage of stars from the 8th to the 13th magnitude, more than filling the field, especially in length, with power 93; thr most compressed part trending sf [south following, SE] and np [north preceding, NW]. Among the larger [brighter] stars on the northern verge is an extremely faint planetary nebula, which is 39 H. IV. [NGC 2438], and 464 of his son's Catalogue. This was discovered by Messier in 1769, who considered it as being "rather enveloped in nebulous matter;" this opinion, however, must have arisen from the splendid glow of mass, for judging from his own remark, it is not likely that he perceived the planetary nebula on the north. WH [William Herschel], who observed it in 1786, expressedly says, "no connexion with the cluster, which is free from nebulosity." Such is my own view of attentively gazing; but the impression left on the senses, is that of awful vastness and bewildering distance, - yet including the opinion, that those bodies besprangled the vastness of space, may differ in magnitude and other attributes.
To fish up this object, an occult line must be carried from Alpha Leporis through Sirius, and extended 13 1/2 deg, or nearly as far again, to the eastward; where a glance from Castor over Procyon passes through it. In the following [eastward] field there is a coarse pair of 7th magnitude stars, lying sf [south following, SE] and np [north preceding, NW] to each other.

John Herschel, General Catalogue: GC 1564.

GC 1564 = h 463 = M46.
RA 7h 35m 24.3s, NPD 104d 29' 50.4" (1860.0) [Right Ascension and North Polar Distance]
!; Cl; vB; vRi; vL; inv PN. 4 observations by W. & J. Herschel.
Remarkable; cluster; very bright; very rich; very large; involving a planetary nebula.

GC 1565 = h 464 = h 3093 = H IV.39.
RA 7h 35m 25.4s, NPD 104d 29' 39.4" (1860.0)
PN; pB; pS; vlE; r; 3s.75 d. 4 observations by W. & J. Herschel.
Planetary Nebula; pretty bright; pretty small; very little extended [elongated]; round; 3s.75 diameter.
Remark: Figure in P.T. 50 [Rosse 1850], plate xxxviii, fig. 12.

Dreyer: NGC 2437.

NGC 2437 = GC 1564 = h 463; M 46.
RA 7h 35m 24s, NPD 104d 29.8' (1860.0) [Right Ascension and North Polar Distance]
!, Cl, vB, vRi, vL, inv PN ; = M46
Remarkable, cluster, very bright, very rich, very large, involving a planetary nebula [NGC 2438].

NGC 2438:
NGC 2438 = GC 1565 = h 464 = h 3093 = H IV.39.
RA 7h 35m 26s, NPD 104d 25.0' (1860.0)
PN, pB, pS, vlE, r, 3s.75 d
Planetary Nebula, pretty bright, pretty small, very little extended [elongated], round, 3s.75 diameter.
Remark: Figures in P.T. 50 [Rosse 1850], plate XXXVIII, fig. 12; Lass [Lassell, Memoirs R.A.S. vol xxiii], plate II, fig. 5; Secchi [Memorie dell' Osserv. del Collegio Romano, 1852-55], plate IV, fig. 11.

Curtis

[Descriptions of 762 Nebulae and Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 2437 and 2438, RA= 7:37.2, Dec=-14:29. [NGC] 2437 is a very large, bright, sparse cluster about 25' in diameter, in which is involved the planetary nebula [NGC] 2438. 0 s.n.