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RA: 08h 10m 25.7s
Dec: −49° 10′ 3″
Ch: MSA:966, U2:396, SA:20
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 13rn
Mag: B=4.75, V=4.7
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This cluster was discovered by Lacaille and included in his 1755 catalogue as Class III No. 2. In his half-an-inch 8x telescope he saw it as "five faint stars like letter T in nebulosity."
Dunlop 410: "A curiosly 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 is a very good representation of the group."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "chief star 7th mag about, of a very large, loose, brilliant cluster of very scattered stars, 1 of 7th mag, 2 of 8th mag, rest 9..16th mag. Fills more than field; 100..150 stars." On a second occassion he called it "a large loose cluster 8th class of large and small stars, full 20' diameter. Has in it about 20 stars above 11th mag, and one neat double star. Place that of a star 8th mag in the following part."
In "Results of Astronomical Observations .. at the Cape of Good Hope" (1847), Herschel notes that this object is Dunlop 411; this is evidently not the case, since Dunlop 411 is the beautiful galaxy NGC 4945.
Perhaps Herschel made a clerical error when he recorded NGC 2547 as Dunlop 411, meaning to write Dunlop 410.
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part III. Southern Objects. M.N.R.A.S., 36(3), 91.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
"cluster, coarse, irregular."
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 17' and the class as 2 3 p.
"A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.
"irregular, with bright stars, visble to the naked eye." He gives the approx. diameter as 20 arcmin.
The RNGC (Sulentic and Tifft 1973) notes that this is a 5.0 mag open cluster.
Harrington calls it a "spectacular open cluster ... more than 80 stars make up this dazzling cast, with more than a dozen shining brighter than 9th magnitude. Many of them appear to form lines and curves, giving me the impression of a crooked cross lying on its side."
Claria? br * V=6.47/-0.15. wide pair V=8.15/-0.01 and 8.42/-0.06.
QBS: f neb over cl.
15cm - nice br cl around m7 `cen *'. brtr *s lie mostly E of brtst. 35' diam w/100 *s @ 80x, little concen twd center. wide pair NE of cen *, but otherwise no mod close pairs. BS, 22Feb1990, LCO.
12-inch f/10 SCT (95x 218x)
This cluster which is situated in the western part of the vela constellation, could well be nick named the "The heart cluster". Willie Koorts draw my attention to the shape of this cluster. After investigation I could whole heartily agree with him. The brighter stars in the grouping are well outstanding in a round half-moon shape towards the eastern side with the brightest member been magnitude 6.4 HD 68468. The pointed heart shape point towards the north. The western part forms the other half with numerous faint stars scattered over the whole surface. The south-eastern part of this lovely cluster is much busier with starlight.
Meade 12", 40mm eyepiece, 53' f.o.v.
Pietersburg; moderate light pollution
LMC just visible, so too Era Car
8h 10m 7s, -49 16
Bright, well condensed cluster, stands out well against the background.
Has a definite triangular shape. Covers three-quarters of the field with a loose collection of stars of varying brightnesses. The eastern corner is beautifully outlined.
16-inch f/10 SCT (102x, 290x)
What a lovely cluster. A handful of bright stars stands out with first impression and mingle well with a mist of faint stars. A 6.4 white star (HD 68478) is dominate the middle part with two visual double stars to the N and NW. Towards the East edge of the cluster a faint small knot of splinter stars can be seen. Very much open cluster which should be easy in binoculars.
Stellenbosch (Paradyskloof Rifle Range)
11x80 tripod-mounted binoculars (12.5-mm aperture mask)
Conditions: Dark moon. Slight easterly breeze. NELM approx 5.5 at the pole. Dew.
One star of about 7th magnitude central in a rich cluster of much fainter stars. This bright star lies one-third of the way along a slender north-south arc of stars. From near the centre of this arc, a shorter dash of stars extends to the northwest, giving the whole the shape of a tau. Through the 12.5mm, I would agree with Lacaille's count of "five small stars." Lacaille's description: Star count, OK, shape OK.
1998-01-24/25, 6-inch f/8.6 Newtonian, Stellenbosch Rifle Range site. 22:00 SAST. Fills the 30' field of the K18mm with curved looping chains of stars enclosing two dark patches. These two patches, and the surrounding chains, form a lob-sided comic-heart. With the wider field of the 25-30mm, the outliers of the cluster also lie in loops. This loose structuring displays minimum concentration. Large range in brightness: some very faint, others 8th magnitude, but no one star central or dominating. All stars white, no colours noticed. No haze from unresolved background stars.
1998-04-27/28, 11x80 tripod-mounted binoculars, Die Boord. Seeing average, transparency average, dew. "Prominent in a rich field while sweeping, this cluster is easy to find 2° south of the brilliant white gamma Velorum. A large 16' irregular grouping (narrowing at one point to 12'), moderately bright, clearly resolved into stars of mixed magnitudes (one vB*, 10 mod. B*s and a sprinkling of vF*s). The brightest star may be somewhat orange-tinged; the others are too faint for colour-detection."
1995-05-30: 11x80.Technopark. 21:30 SAST. Hazy sky. Noticeable open cluster near Gamma Vel. It is an irregular triangle-shaped group of over a dozen stars, one of which is considerably brighter. This primary doesn't have any particular colour.
1994-12-04, Die Boord, 6-inch f/8.6 Newtonian. Interesting loose cluster of large and small stars. It is a large scattered grouping of about 10 brighter stars and 20 fainter members. Five of the brighter stars make a north-south curved loop which becomes a spiral at the southern end.
2008 March 02, 21:00
Walmer, Port Elizabeth
2.5-inch f/7.6 refractor (EP: 12.5mm 56x 30arcmin fov)
Conditions: Windy, clear.
Size=20arcmin, V=4.7. Fairly bright, noticeable cluster, moderately easy to find, of generally equal spacing with dark starless patches. About 13 stars were visible through the eyepiece (12.5mm); brightness of cluster predominantly uneven M6.8 to M9. Bright central star M6.9 further northwest another prominent star in the cluster M6.8 the remainder of the stars fall between M7.1 to M9. NGC 2547 forms two chains: a brighter semi-circular chain M6.8 to M8 running northwest to southwest; featuring the two prominent stars. The other chain running southwest to north-northeast contains dimmer stars M8.4 to M9.3. Many field stars in the area, prominent field stars in the northwest 22arcmin M6 HD 68161, and 32arcmin north M6.1 HD 68657. Groupings one degree east, two stars M8.6 and M8.2.
The Messier objects
The Bennett objects
The Caldwell list
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