Lacaille’s NGC and IC objects

[glenc (Glen)]

Between September 1751 and June 1752 the Frenchman Nicolas-Louis de Lacaille (1713-1762) discovered 24 new NGC and IC objects; 17 open clusters, 4 globular clusters, 2 nebulae and a galaxy with a 0.5” aperture refractor from Cape Town.

He also catalogued 9766 stars and named 14 southern constellations. Not a bad effort! His list was made before Messier started his catalogue. Some discovery dates, first published here, are uncertain.

The attached table gives the NGC or IC number (with 2 Messier numbers), the constellation, the type and sub-type, the date found, YMD, the magnitude and the size in arc-mins.

[glenc (Glen)]

The following Lacaille and Dunlop descriptions are from
Steve Gottlieb's NGC/IC Notes.
http://adventuresindeepspace.com/steve.ngc.htm

NGC 104 TUC GC
Nicolas-Louis de Lacaille discovered the nebulous appearance of NGC 104 = Lac I-1 = D 18 = 47 Tucanae = h2322 in 1751-1752 with a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. It appeared "like the nucleus of a fairly bright comet." He placed it in group I, consisting of nebulae without stars.

With his 9-inch speculum reflector, James Dunlop logged "(47 Toucan, Bode) this is a beautiful large round nebula, about 8' diameter, very gradually condensed to the centre. This beautiful globe of light is easily resolved into stars of a dusky colour. The compression to the centre is very great, and the stars are considerably scattered south preceding and north following." His sketch (figure 1 in his catalogue) shows a beautifully resolved, elongated cluster.

NGC 2070 DOR Neb
Nicolas-Louis de Lacaille discovered NGC 2070 = Lac I-2 = D 142 = h2941 in 1751-1752 using a half-inch refractor at 8x during his expedition to the Cape of Good Hope. He included it in his 1755 catalogue as Class I No. 2 and remarked "like the former [NGC 104: "like the nucleus of a fairly bright comet] but faint."

James Dunlop made 8 observations and reported 30 Doradus as "a pretty large ill-defined nebula, of an irregular branched figure, with a pretty bright small star in the south side of the centre, which gives it the appearance of a nucleus. This is resolvable into very minute stars. Figure 4. is a very good representation of the nebula resolved. (N.B. The 30 Doradus is surrounded by a number of nebulae of considerable magnitudes, nine or ten in number, with the 30 Doradus in the centre.)"

IC 2395 VEL OC
Nicolas-Louis de Lacaille discovered IC 2395 = Lac. III-3 between 1751-1752 during his expedition to the Cape of Good Hope. He recorded "Star of 6th magnitude, connected to another more southern one by a nebulous trail."

NGC 2477 PUP OC
Nicolas-Louis de Lacaille discovered NGC 2477 = Lac I-3 = D 535 = h3103 in 1751-1752 using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He recorded a "large nebula 15' to 20' diameter."

James Dunlop made 5 observations (first on 7 May 1826) and described the cluster as "a pretty large faint nebula, easily resolvable into small stars, or rather a cluster of very small stars, with a small faint nebula near the north preceding side, which is rather difficult to resolve into exceedingly small stars. This is probably two clusters or nebula in the same line; the small nebula is probably three times the distance of the large nebula." His position was ~12' too far NW.

IC 2488 VEL OC
Nicolas-Louis de Lacaille discovered IC 2488 = Lac III-4 = D 330 between 1751-1752 using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He described it as a "Faint star surrounded by nebulosity"

James Dunlop made two observations on 8 May and 3 Jul 1826 with summary description "A faint cluster of small stars of mixed magnitude, with two or three pretty bright stars in it. This answers to 485 Argus (Bode) and is described as a small star surrounded by a nebula." John Herschel didn't record this large naked eye cluster during his observations at the Cape of Good Hope, so it didn't receive a JH, GC or NGC designation.

NGC 2516 CAR OC
Nicolas-Louis de Lacaille discovered NGC 2516 = Lac II-3 = h3111 in 1751-1752 using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He noted a "Group of 10 to 12 stars, very compressed."

NGC 2516 was not included in Dunlop's main catalogue but his handwritten notes call it a "Very fine cluster about 35' diameter, many of the stars of the 6th and 7th magnitude, mixed magnitudes. Figure irregular - branched."

NGC 2546 PUP OC
Nicolas-Louis de Lacaille discovered NGC 2546 = Lac II-4 = D 563 = h3116 in 1751-1752 using a 1/2-inch refractor at 8x during his expedition to the Cape of Good Hope. He recorded II-4 as follows: "One sees with the naked eye two neighboring confused groups of stars; but with the telescope they are faint, distinct stars, very numerous & very close together."

James Dunlop observed the cluster on 8 May and 28 May 1826 and recorded, "a large cluster of stars of mixt magnitude, rather extended figure, not rich in very small stars." His position was 17' too far north (typical error). John Herschel made 3 observations from the Cape of Good Hope, reporting on 1 Feb 1835 "a cluster 8th class of about 20 bright stars in an oblong, 8' long, 3' broad."

NGC 2547 VEL OC
Nicolas-Louis de Lacaille discovered NGC 2547 = Lac III-2 = D 410 = h3117 in 1751-1752 using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He described "five faint stars like the letter T in nebulosity."

Dunlop observed the cluster twice (first 28 May 1826) with summary description, "A curiously arranged group of pretty bright small stars of mixt magnitudes. This answers to the place of 310 Argus (Bode) and is described by Lacaille as nebula with five small stars forming the letter T in it. There is no nebulosity in this place. The diameter of the cluster may be about 12'. Figure 16 [in his publication] is a very good representation of the group."

IC 2602 CAR OC
Nicolas-Louis de Lacaille discovered IC 2602 = Lac II-9 in 1751-1752 with a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He recorded "The star Theta Navis, of the third magnitude or less, surrounded by a large number of stars of 6th, 7th & 8th magnitude, which resemble the Pleiades." The nickname "Southern Pleiades derives from this description. John Herschel did not record this large naked eye cluster during his observations at the Cape of Good Hope, so it did not receive a GC or NGC designation.

NGC 3228 VEL OC
Nicolas-Louis de Lacaille discovered NGC 3228 = Lac II-7 = D 386 = h3245 in 1751-1752 with a 1/2-inch telescope at 8x. He called it a "heap of four or five stars, very small and compressed."

James Dunlop observed the cluster twice outside Sydney, Australia (first on 9 May 1826) and reported "11 Roboris Caroli. A group of 8 or 10 pretty bright small stars, with very small stars, about 6' diameter." On 6 Apr 1834 (sweep 438), John Herschel called this "a group of 9 large, and a few scattered small stars."

NGC 3293 CAR OC
Nicolas-Louis de Lacaille discovered NGC 3293 = Lac II-8 = D 321 = h3276 in early 1752, using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He described a "Small heap of 4 small stars forming a lozenge."

James Dunlop observed the cluster 4 times (first on 29 Apr 1826) and described "a very small cluster of very small bright stars; round figure, about 4' diameter; rich in extremely small stars resembling faint nebula". His published position was poor -- 17' WSW of the cluster.

[glenc (Glen)]

The following Lacaille and Dunlop descriptions are from
Steve Gottlieb's NGC/IC Notes.

NGC 3372 CAR Neb
Nicolas-Louis de Lacaille discovered (telescopically) NGC 3372 = Lac III-6 = D 309 = h3295 in 1751-1752 with a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He recorded a "Large group of a great number of small stars, little compressed, and filling out the space of a kind of a semi-circle of 15 to 20 minutes in diameter; with a slight nebulosity spreading in that space." Of course, the nebula and embedded clusters is a prominent naked-eye object, so was certainly known by southern sky watchers.
James Dunlop observed it at least 13 times beginning on 30 Mar 1826. His summary description reads "(Eta Roboris Caroli, Bode) is a bright star of the 3rd magnitude, surrounded by a multitude of small stars, and pretty strong nebulosity; very similar in its nature to that in Orion, but not so bright... I can count twelve or fourteen extremely minute stars surrounding Eta in the space of about 1'; several of them appear close to the disk: there is a pretty bright small star about the 10th magnitude N.f. the Eta, and distant about 1'. The nebulosity is pretty strongly marked; that on the south side is very unequal in brightness, and the different portions of the nebulosity are completely detached, as represented in the figure [plate III, figure 14]. There is much nebulosity in this place, and very much extensive nebulosity throughout the Robur Caroli, which is also very rich in small stars."

NGC 3532 CAR OC
Nicolas-Louis de Lacaille discovered NGC 3532 = Lac II-10 = D 323 = h3315 in 1751-1752. Using a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope, he described a "prodigious number of faint stars forming a semi-circle of 20 to 25 minutes diameter."
James Dunlop observed the cluster 3 times, including 27 Apr 1826, his first night recording clusters and nebulae. He described "a very large cluster of stars about the 9th magnitude, with a red star of the 7-8th magnitude, north following the centre of the cluster. Elliptical figure: the stars are pretty regularly scattered."

NGC 3766 CEN OC
Nicolas-Louis de Lacaille discovered NGC 3766 = Lac III-7 = D 289 = h3352 in 1751-1752 from the Cape of Good Hope. Using his 1/2-inch telescope at 8x, he noted "three faint stars in nebulosity".
James Dunlop observed the cluster on 27 Apr 1826, his first night logging nebulae and clusters. He described a "A pretty large cluster of stars of mixt magnitudes, about 10' diameter. The greater number of the stars are of a pale white colour. There is a red star near the preceding side; another of the same size and colour near the following side; another small red star near the centre; and a yellow star near the south following extremity, all in the cluster."

NGC 4755 CRU OC
Nicolas-Louis de Lacaille discovered NGC 4755 = Lac II-12 = D 301 = h3435 in 1751 through a 1/2" telescope during his expedition to the Cape of Good Hope. He classified it as a nebulous star cluster and noted "5 or 6 small stars between two of sixth magnitude". The cluster was observed at the Parramatta Observatory during regular meridian work and described as "a cluster of 12 or 14 small stars, in the form of a rhomboid, very close together. Part of this cluster forms a very perfect cone of mixed stars."
On 26 May 1826 at Parramata, James Dunlop described "(Kappa Crucis, Bode) is 5 stars of the 7th magnitude, forming a triangular figure with a star of the 8 or 9th magnitude between the second and the third, with a multitude of very small stars congregated around the 4th or most southerly star on the south side." Based on 6 observations with his 9" speculum reflector, he noted "Figure 13 [sketch] is a very correct representation."

NGC 4833 MUS GC
Nicolas-Louis de Lacaille discovered NGC 4833 = Lac I-4 = D 164 = h3444 in 1751-1752 with a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He included it in his 1755 catalogue as I-4, classifying it as a nebula, and noting it resembled "a small faint comet."
James Dunlop observed this globular with his 9-inch f/12 speculum reflector on 29 Apr 1826 (second night he recorded objects). His summary description reads "a pretty bright round nebula, about 4' diameter, moderately condensed to the centre. This, with the sweeping power, has the appearance of a globe of numerous matter with very small stars in the north following margin. But with a power sufficient to resolve it, the globular appearance vanishes in a very considerable degree; and the brightest and most condensed part is to the preceding side of the centre, with the stars considerably scattered on the N.f. side. Resolvable into stars of mixt small magnitudes." He observed the cluster on 5 nights.

NGC 5236 M83 HYA The 3rd galaxy to be found with a telescope
Nicolas-Louis de Lacaille discovered M83 = NGC 5236 = Lac I-6 = D 628 = h3523 in 1751-1752 with only a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He simply described a "small, shapeless" nebula. M83 is the only galaxy in Lacaille's list and it's remarkable he discovered it with so small an aperture.
Charles Messier was barely able to view it from Paris, noting "It appears as a faint, even light, but is difficult to see with the telescope that the slightest illumination of the micrometer's crosshairs causes it to disappear. It requires considerable concentration to see at all."
James Dunlop observed M83 on 29 Apr 1826 (his second night recording deep sky objects) and 4 additional nights. His summary description reads, ".. a very beautiful round nebula, with an exceedingly bright well-defined disk or nucleus, about 7 or 8 arcseconds diameter, surrounded by a luminous atmosphere or chevelure, about 6' diameter. The nebulous matter is rather a little brighter towards the edge of the planetary disk, but very slightly so. I can see several extremely minute points or stars in the chevelure, but I do not consider them as indications of its being resolvable, although I have no doubt it is composed of stars." His published position was off by some 12+ minutes in RA due to a transcription error but his handwritten notebook position is within 10' of center.

NGC 5281 CEN OC
Nicolas-Louis de Lacaille discovered NGC 5281 = Lac I-7 = D 273 = h3531 in 1751-1752 during his expedition to the Cape of Good Hope. With a 1/2" telescope at 8x he noted a "small indistinct spot."
James Dunlop made 7 observations, starting 25 May 1826, and described "a curved line of small stars, about 1.5' long, with a star of the 7th mag in the north extremity; a group of extremely minute stars on the preceding side of the crescent, and a multitude of very minute stars extended preceding and following." (Fig. 11)

NGC 5662 CEN OC
Nicolas-Louis de Lacaille discovered NGC 5662 = Lac III-8 = D 342 = h3573 in 1751-1752 with a 1/2" telescope at 8x during his expedition to the Cape of Good Hope. It was included in his 1755 catalogue as Class III No. 8. and noted as "two stars in nebulosity."
James Dunlop observed the cluster on 25 May 1826 and recorded "A group of small stars of the 11th and 12th mag, with a multitude of minute stars mixt, extended south preceding and north following, pretty regularly scattered."

NGC 6025 TRA OC
Nicolas-Louis de Lacaille discovered NGC 6025 = Lac III 10 = D 304 = h3616 in 1751-1752 using a 1/2" telescope at 8x during his expedition to the Cape of Good Hope. With this small telescope he noted "three faint stars in line in nebulosity."
James Dunlop made 5 observations (first on 8 May 1826) with summary description, "(Lambda Circini, Bode) Lacaille describes this as three small stars in a line with nebula. No particular nebula exists in this place. A group of about twenty stars of mixt magnitudes, forming an irregular figure, about 5' or 6' long, answer to the place of the Lambda. This is in the milky way; and there is no nebula in the group of stars except what is common in the neighbourhood."

NGC 6124 SCO OC
Nicolas-Louis de Lacaille discovered NGC 6124 = Lac I-8 = D 514 = h3626 in 1751-1752 with a 1/2" telescope at 8x. It described it as "a fairly big tailless comet."
James Dunlop observed the cluster on 5 nights (first on 10 May 1826) with summary description, "a round cluster of small stars of nearly equal magnitudes, about 12' diameter, considerably congregated to the centre, not rich in small stars. This answers to the place of 44 Normae, but there is no nebula."

NGC 6242 SCO OC
Nicolas-Louis de Lacaille discovered NGC 6242 = Lac I-10 = D 520 = h3654 in 1751-1752 with a 1/2" telescope at 8x, during his expedition to the Cape of Good Hope. He simply noted an "elongated faint oval spot."
James Dunlop made 3 observations with his 9-inch f/12 reflector in 1826. His description from 13 May reads, "a cluster or group of small stars, about 4' diameter, with extensive branches extending S.p. and N.f. A pretty bright star south of the center. Considerable compression of the stars towards the centre of the group."

NGC 6397 ARA GC
Nicolas-Louis de Lacaille discovered NGC 6397 = Lac III-11 = D 366 = h3692 in 1751-1752 with a 1/2" telescope at 8x, during his expedition to the Cape of Good Hope. He simply noted "faint star in nebulosity."
James Dunlop independently found this globular on 28 Jun 1826 with his 9-inch reflector and described "a pretty large nebula, extended nearly in the parallel of the equator, brightest and broadest in the middle; a group of very small stars in the middle give it the appearance of a nucleus, but they are not connected with the nebula, but are similar to other small stars in this place which are arranged in groups. The nebula is resolvable into stars." Dunlop made 4 observations in June and July and his position was 5' east of center.

NGC 6809 M55 SGR GC
Nicolas-Louis de Lacaille discovered M55 = NGC 6809 = Lac I-14 = D 620 = h3798 in 1751-1752 during his expedition to the Cape of Good Hope. Using a 1/2-inch refractor at 8x he described it "like the obscured nucleus of a big comet."
Messier made an unsuccessful search on 29 Jul 1764 (perhaps due to the southern declincation), but succeeded in July 1778, recording "a nebula which is a whitish spot; extending for 6' around the light is even and does not appear to contain a star."
James Dunlop described the cluster as "a beautiful, large round bright nebula, about 6' or 7' diameter, moderately condensed gradually to the centre, easily resolvable." His position was over 20' too far east. On 3 Aug 1834 (sweep 478), John Herschel recorded "Globular cluster; pB; vL; R; very gradually little brighter middle; diam in RA 30.0s; all resolved into separate st 13...16 m; not so comp M as to run together into a blaze or nipple. "