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Lacaille III.10 (13,409 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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Lacaille III.10

Lacaille III.10, Dunlop 304, NGC 6025, Cl Collinder 296, C 1559-603, Cl VDBH 181, COCD 366, Caldwell 95, h 3616, GC 4153

RA: 16h 03m 18s
Dec: −60° 26′ 0″

Con: Triangulum Australe
Ch: MSA:1512, U2:432, SA:26

Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)

(reference key)

Type: open cluster, 23r

Mag: B=5.26, V=5.1

Size: 14′
PA: ?

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Sketches  (1)

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Historical observations

Lacaille (1755)

This cluster was discovered by Lacaille and included in his 1755 catalogue as Class III No. 10. In his half-an-inch 8x telescope he saw it as "three faint stars in line in nebulosity."

Dunlop, James (1827)

James Dunlop observed this object from Paramatta, New South Wales, and included it as No. 304 in his catalogue of 1827. Using a 9-inch f/12 telescope, he recorded it on 5 occasions, describing it as "(Lambda Circini) 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."

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 "large, brilliant cluster VII class; fills field, not rich, stars 8, 9, 10, 11th mag, with smaller. Chief star 8th mag taken, in the southern part of cluster." On a second occassion he called it "VII.; loose; scattered;brilliant; stars large; much more than fills field; 46 stars counted above 12th mag; chief star 7th mag taken." His third observation was recorded as "Chief star 8th mag of a coarse, pL, cluster of stars, 8..11th mag, which fills the field." The final record reads: "Chief star 7th mag of a large, oblong, bright scattered cluster, stars 7..10th mag."

Published comments

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.

Melotte, P.J. (1915)

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

Doig, P. (1925)

Journal BAA, 36(3), Dec, p91

mainly of B *s; diam. 20', irr. outline, two groups in centre.

Hogg, A.R. (1965)

"Cat. of Open Cl. south of -45 Decl.", Mem. 17 Mnt Stromlo Obs.

Doig, P. (1926)

"A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.

"irregular; bright stars; two groups." He gives the approx. diameter as 15 arcmin.

Trumpler, R.J. (1928)

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 11' and the class as 2 3 p.

Sanford (1989) Observing the Constellations

Sanford calls it a "small open cluster (10' in diameter) with about 30 stars of 7th magnitude and fainter."

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 6.0 mag open cluster.

Bailey, S.I. (1908)

"cluster, coarse."

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

Photo index

Photo Index by Jim Lucyk: Ast.Obj.for South.Tel. (Hartung, 1984).

James, Andrew (1998+)

From: "Neat Southern Planetaries - IV."

NGC 6025 (Mel 139 Cr 296) (16037 6029) is an open cluster two degrees east and 10'min.arc. north of NGC 5979. As a cluster it can just be discerned as a lucid spot to the naked eye and easily visible in any finder. The fourteen bright stars in this cluster are visible in a 7.5 cm. telescope. Larger telescope (>20cm.) reveals more stars, with about twenty-five being brighter than 14th magnitude in an area of 12'min.arc2. Total integrated visual magnitude of the cluster is 5.1 and five stars are brighter than 9th magnitude. Brightest is the 7.3 magnitude star GSC 9036 2707. Deep astrophotography reveals about sixty associated stars, though some of the stars to the NW are not attached to the cluster. It is given a Trumpler classification of '2 3 r' A weak concentration towards the centre with a large range in brightness and has a population that is rich.

At Bowen Mountain on the 23rd August 1997, Don Whiteman though it was "pretty neat and nice" through the Society's 45 cm. My personal belief is that the cluster is fairly elegant.

In reality, the cluster is about 2.9 parsecs (9 lty.) across, and has an estimated distance of 800 pc. (2 600 lty.). The age of this B3 spectral class metal poor cluster, as calculated by the turn off point on its colour magnitude diagram, is calculated to about seventy million years. The cluster is slowly moving away from us at a small 3kms 1.

Modern observations

Brian Skiff

15cm - br rel sparse cl 18' diam. 65 *s @ 80x, only wkly concen, m7-12. fairly

distinct dk patch elong ~E-W on E edge of cl blocks out outliers there.

cl elong SSE-NNW. BS, 24Feb1990, LCO.

Contemporary observations

Auke Slotegraaf


Observing from Stellenbosch, 1983, I saw this cluster in a 2-inch refractor as a loose, poor gathering, forming a "lazy-W" shape in the region where it is most condensed. This coarse collection of stars has only about 3 prominent members and one can easily move right over it and miss it. My rough sketch showed 17 stars in the cluster.


Observing from the 1500 metre plateau of the SAAO observing site in Sutherland, 11x80 binoculars show it as a rather small and somewhat obscure cluster, roughly a quarter of a degree across, lying mainly in a highly elongated north-east to south-west configuration. The south-western tip is marked by a fine, unequal pair of stars. The brighter companion possibly appears slightly red.

1995 May 28

1995-05-28: 11x80.Technopark. 20:15 SAST. Hazy sky, thin clouds. A narrow spray or wedge of stars leading away from an 8th magnitude star. Very noticeable even when sweeping.

1997 April 14

1997 April 14, 02:00 - 04:00 Jonkershoek. 11x80's tripod-mounted. Rectangular collection of stars with a bright, double, primary. About 12 stars seen, rest mottled glow of fainter hoards.

1997 September 03

1997 Sept 03: 11x80 tripod-mounted. 23:00 SAST. Jonkershoek. Very bright, much elongated cluster (1:5 ratio). An almost equal double star lies in the south-eastern tip, the cluster being oriented Sout-east to North-west [earlier comments in error?]. Crossing this elongated section, running north-south, is a row of fine stars.

1998 April 01

1998-04-1/2, 11x80 tripod, Stellenbosch Rifle Range site, polar naked eye lim mag 6.0, darkness average, transparency very good. Bright well populated cluster, responds well to averted vision.

1998 April 27

1998-04-27/28, 11x80 tripod-mounted binoculars, Die Boord. Seeing average, transparency average, dew. "A bright easy object, stars from 8th magnitude down to a hazy glow. Elongated NW-SE, measuring 20' x 6.5'. Perhaps only half-dozen stars honestly resolved out of this tight grouping. There is one much brighter star marking the southeastern edge; this is double, with the companion about half a magnitude fainter. In the centre of this elongated grouping there is a bar of stars running north-south."

1993 April 30

30/04/93: Observing with a 6-inch f/8.6 Newtonian, this large cluster shows about 15 9th mag and a few fainter stars, lying in an irregular Z-shaped chain extended north-south. The cluster is bright, vL, with an estimated Trumpler class of III 2 m. It is nicely shown at 108x. The southern end of the Z shape ends in a pair of bright stars and is somewhat isolated from the rest of the group, so that the cluster could be described as being V-shaped pointing to the north-east with a few stars (of which two are bright) in the south. The brightest star in the cluster is one of the southern two. In all, about 33 stars are counted in this quite brilliant grouping.

Gerrit Penning

2004 April 18, 21:32 UT

Boyden Observatory, Bloemfontein, South Africa

8-inch refractor, Boyden Observatory

A beautiful and large populated open cluster with relatively bright stars.

Magda Streicher

14 June 2009


RA: 16h03m18s - DEC: -60o25' - Magnitude: 5.1 - Size: 15'

Tel: 12" S/C 218x - Date: 14 June 2009 Seeing 5.6

The swing along cluster, round and round it goes. A pair of bright stars situated at the southern tip of the cluster from where stars string along in an elongated formation north wards. The major string in an 'S' shape also the focus point in the northern part of the cluster. What an outstanding grouping very nice.

23 May 2009


RA: 16h03m17s - DEC: -60o25'9" - Magnitude: 5 - Size: 14'

Tel: 12" S/C 218x - Date: 23 May 2009 Seeing 5.7

Nice outstanding against the star field. This cluster comprises two groups with each one in a special way. The larger group is larger and more prominent to the north western side where as the smaller group is more in a round spaced shape of around six stars.

(no date)

Alldays (22.50S, 20.12E, 770m).

12-inch f/10 SCT (218x, 346x)

The dark nebula is seen with the scattering of stars, which is in a NS direction. Fountain of stars curl out in between part of the dark nebula. The bigger part of the dark nebulosity can be seen to the east, forming a large roundish cloud. This cluster immediately remind me of the Mac Donald sign or Japanese fan spraying out towards the NW. Even a real M with stars that vary between 11 and 7 magnitude is a possibility.

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