Lacaille I.3

Historical observations

Lacaille (1755)

This open cluster was discovered by Lacaille and included in his 1755 catalogue as Class I No. 3, classifying it as a nebula. In his half-an-inch 8x telescope he saw it as a "big nebula 15' to 20' diameter."

Dunlop, James (1827)

James Dunlop observed this object from Paramatta, New South Wales, and included it as No. 535 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it 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." Dunlop recorded this cluster on 5 occassions.

John Herschel (1847) Cape Observations

Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "Superb cluster, gbM, 20' diameter, much more than fills the whole field. Stars 10 and 11th mag all nearly equal." On a second occassion he called it "Cluster 6th class, bright, large, rich, not very highly condensed in the middle. Stars very remarkably equal. All 12 or 13th mag. Very few 14th mag; none 11th mag. A fine object." His third observation was recorded as "a very beautiful large cluster, very rich; stars nearly equal, and 12th mag, gbm, not much compressed in the middle; more than fills the field. (N.B. It is visible in the finder of the equatorial, and in the telescope of that instrument appears as a fine cluster."

Published comments

Trumpler, R.J. (1928)

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 25' and the class as 1 2 r.

Raab, S. (1922)

Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.

Discussed, based of F-A plates.

Doig, P. (1925)

Journal BAA, 36(3), Dec, p91

fine circular, almost glboular, cluster about 30 ;diam., with condensation; no B*.

Shapley, H. (1930)

"Star Clusters" Harvard Obs. Monographs No. 2.

p 19: "In superficial appearance, NGC 2477, galactic longitude -5°, is the richest of galactic clusters; or perhaps it is the loosest of globular clusters. No variables have been found within it, but the examination has not been exhaustive. .. For the present, we leave NGC 2477 in the list of galactic clusters, awaiting further photometric and spectroscopic analysis with larger telescopes."

Bailey, S.I. (1908)

"! cluster, fairly condensed."

Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.

Burnham's Celestial Handbook

Burnham calls this "probably the finest of the galactic clusters in Puppis." The NGC calls it a remarkable cluster, rich and well spread-out, consisting of stars of 12th magnitude. Burnham notes that it is a "striking group, somewhat smaller than M46, but richer and more compact." P. Doig called it "almost globular" and Shapely wrote of it as "in superficial appearance... the richest of galactic clusters; or perhaps it is the loosest of globular clusters."

Melotte, P.J. (1915)

A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.

Helwan Obs. Bulletin No 9 (1912)

A loose cluster

Photo index

Photo Index by Jim Lucyk: Deep Sky #13 Wi85 p18, Deep Sky #17 Wi86 p10, Burnhams V3 p1517.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 5.5 mag open cluster.

Modern observations

Hartung, E.J. (1968) Astron.Obj.South.Tel

Hartung writes that the cluster is "broadly concentrated to a dense centre of 12'; the stars are very numerous and many are grouped in curved lines and sprays with dark sky between, making a beautiful effect. A 6" shows this cluster fairly well."

Harrington, Phil

Harrington says the cluster "appears like a ball of celestial cotton spanning about a Moon's diameter when viewed through low-power binoculars. With a rich-field telescope, the cluster's fuzziness dissolves into a myriad of faint points of light. In all, 160 stars dwell within NGC 2477, though none shine brighter than 10th magnitude."

Cozens, Glen

Glen Cozens notes that "a moderate aperture will show it as well-resolved stars against a grainy background of faint starlight."

Steve Coe

Steve Coe, observing with a 13" f/5.6, notes: "Bright, large, very, very rich, very compressed. 180 total members estimated by counting 45 stars in the northeast quadrant at 100X. There are many lovely dark lanes that wind there way through several star chains and an ever-present glowing backround of more stars. I can resolve 20 stars in the 11X80 finder."

Tom Lorenzin

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "6M; 25' diameter; hundreds of 10M and dimmer members; use wide field at 50x; great binocular object just N of 4M b PUP."

Contemporary observations

Auke Slotegraaf

1983

A really beautiful sight; 11x80 binoculars show it as a large round, nebulous patch, with no stars; a bright star, b Pup, lies to its southeast. The cluster is easy to locate, since it lies north of the pretty bright b Puppis. A hasty glance shows nothing, but the slightest averted vision shows a glorious glow, a faint glimmer of starlight, which is remarkabley large. This is quite unexpected, because you don't expect a patch of barren sky to suddenly burst into a puff of starlight. It looks like the faint extended halo of a comet. Contrasts nicely with nearby NGC 2451.

1995 May 30

1995-05-30: 11x80.Technopark. 21:30 SAST. Hazy sky. Fantastic! A perfectly insubstantial object. Difficult to judge its shape - it appears round. It is the slightest of glows imaginable, not a star in sight. Remarkable.

1992

A 10-inch f/5 at 30x evenly resolves the cluster into small stars; it appears just under a third of a degree across, and although it has an irregular outline, the stars are pretty evenly distributed across the surface; there does, however, appear to be a more concentrated triangular region cutting right across the cluster's surface. At 66x, about half a dozen brighter-than-average (10th mag) stars are distributed across the clusters surface, causing it to appear lumpy and irregularly condensed. The textured appearance of this remarkable cluster is most pleasing. It really is a most beautiful sight, and forms a nice contrast with the bright star (b Pup) which can be seen in the same field; it sort of looks as if once there were two bright stars here, and one suddenly disintegrated into faint shards of light.

1998 January 24

1998-01-24/25, 6-inch f/8.6 Newtonian, Stellenbosch Rifle Range site. 23:00 SAST. What a splendid object! Exquisitley minute stars almost fill the half-degree K18mm field of view. The cluster appears distinct from the background sky, a myriad stars evenly but densely spread out. This extremely rich gathering has no central star or otherwise dominant member. There is a chain of stars leading off to the north-east.

The dark lanes are very noticeable in this cluster.

The cluster has a bright triangular stellar region, defined on the east and north by the two dark lanes, which intersect at an almost 90 degree angle. The eastern dark lane ends in a definite bulbous lobe, whcih is the most prominent in the cluster. The dark lane making the southern edge also has a bulbous ending; the cluster seems to vaguely extend beyond this barrier.

These two dark lanes look somewhat like golfclubs, crossed near their handles with the heads facing inwards.

(caption)

B: The larger body of the cluster

A: a brighter, triangular region

C: a third smaller dark area, highlighting 'A'

D: a vague soft stellar region

The effect of the dark lanes on the shape of the cluster is quite noticeable. At low (finding) power initially, and afterwards, the impression is created that the cluster is box-shaped, with the eastern edge more sharply outlines.

2002 June 20

2002 June 20, 20:00. 11x80 tripod-mounted. Stellenbosch Rifle Range site. First-quarter moon. Slight easterly breeze. Working on U 362.

Elegant, large, vaguely round puff of star-smoke, almost lost in the bright moonlight.

The bright star just south of the cluster, QZ Puppis, is CD-38°3769 (BSC5:3084) V=4.5, B-V=-0.19. Hoffleit & Warren, in "Preliminary Version of the Bright Star Catalogue, 5th Revised Edition" notes about this star: "Called b Pup in Argelander and most modern catalogues. Was originally called a Pup by Lacaille (1763)."

Gerrit Penning

2004 May 29

Date observed: 29/05/2004

Location: Boyden Observatory, Bloemfontein

Limiting Magnitude: 5

Transparency: Clean & Clear

Light Pollution: 60% moon

Weather conditions: Clear skies, slight cold wind

Instrument: 8" Refractor, 30 mm eyepiece, 25' fov

General impression of object: A fine and intricate "fuzzy" through binoculars. Easy to find due to proximity of bright Puppis stars. Appears almost like a faint but large globular cluster through binoculars. A great sight through larger magnification of medium telescope-almost uncountable amount of stars. In the class of NGC 3532, only on a fainter scale.

Rating: 8.5/10

General impression of its surrounding area: [Binocular] SAO 198545 (mag 4.5) in close vicinity to OC. Bright open cluster NGC2541 in same field of view, making the area truly an impressive sight in the sky.

Description of object:

[Telescope]: This open cluster filled the entire field of view of the telescope's eyepiece. Dozens of faint stars makes it most certainly one of the most highly populated open clusters in the sky for medium telescopes. No specific bright stars dominate the cluster, all appear to have similar size, colour and brightness. Using concentration, it is almost as if the cluster takes on a skewed square, even rectangular shape. One part of the cluster appears to form a triangle, hosted by three brightish stars. Appears to have a slight condensation to the centre of the cluster. A few fainter scattered stars line the edges.

[Binocular]: (12x50) - A prominent "fuzzy" object which appears like a large, hazy and smooth globular cluster through the binocular

Remarks: (How good or bad the observation was and reasons)

Slight hindrance from the moon, though no difficulty existed in identifying faint individual stars. Easily found.

Richard Ford

2012 March 24th, Sat

Location:Perdeberg.

Time:11:15pm.

Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.

Instrument:12-inch Dobsonian.

This open cluster looks like an old cluster of faint stars in the magnitude range of 9 to 11th magnitude stars and a matter of fact that this cluster is well detached.All of the old stars are more or less as bright as each other.In overall all the stars in this open cluster is strongly concentrated towards each other.This open cluster measures 14.2'*4.7'.The stars in the center of this open cluster is slightly brighter compared to the stars on the far outskirts of this cluster.