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Type: association of stars
Mag: B=?, V=9.4
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NGC 1763 is a bi-lobed complex of HII regions and star clusters in the LMC. JH's descriptions and positions from five different sweeps are appropriate, though he was not happy with one of his RA's.
John Herschel recorded it as "very bright, very large, irregularly extended, irresolvable but thickly dotted with many distinct stars." His second observation recorded it as "very bright, very large, much elongated; stars seen." The next observation recorded it as "a very bright, very large nebula with stars (the chief of which in the anterior part of the nebula taken) of a crooked rounded oblong shape. A fine object." His next observation was recorded as "bright; 4' long; 2.5' broad." His final observation reads: "very bright, very large, irregular oval figure with stars in it."
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part V. M.N.R.A.S., 36(3), 89.
Hinks, A. R. (1911) On the galactic distribution of gaseous nebulae and of star clusters. MNRAS, 71(8), 693-701.
IC 2115 (Harvard List 87) = NGC 1763 vB, vL, viE.
[Harvard list = Stewart, D. (1908) Nebulae discovered at the Harvard College Observatory. Annals of Harvard College Observatory, 60(6), 147-194.]
Diffuse nebulae and nebulous groups. Harv. College Obs. Circular, No. 271, 6.
"Several of these [diffuse nebulae in the LMC], as Hinks noted in Monthly Notes, 71, 694, 1911, have been assigned numbers in the Index Catalogue as well as in the NGC. But Hinks erroneously identifies IC 2115 with NGC 1763."
Shapley gives NGC 1763 as a "nebulous group, 30[parsecs]x20[parsecs], 80° - about 15 stars, 11.5 and fainter, included in integrated magnitude" and IC 2115 (deltaRA = 0.2m, deltaDec = 2 arcmin) as "Stellar, planetary".
"cluster, fiarly condensed, irregular, somewhat nebulous; LMC."
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
Remarks, p.217: "Several objects, in this and adjacent clusters, have a gaseous spectrum, in addition to which there appears to be a diffused neb. See H.C. 60."
According to Henize (Catalogues of Hydrogen Alpha Emission Stars and Nebulae in the Magellanic Clouds, Astrophysical Journal Supplement 2, 1956, p315), his object LH N 120-11B "Includes NGC 1763 = HD 32256 P and IC 2115 = HD 32279 Pc" This nebula measures 4.4' east-west and 3.5' north-south, has a somewhat irregular outline, is pretty elongated and shows appreciable structure. Three B-type exciting stars are involved, mags. 11.3, 11.5 and 11.8.
NGC 1763 lies within the LMC O-association No. 10. (Hodge, P.W. and Lucke, P.B., Astronomical Journal, Vol 75, No. 8, 1970, p933-937)
Shapley and Lindsay ("A Catalogue of Clusters in the Large Magellanic Cloud", Irish Astronomical Journal, Vol. 6, 1963) give a diameter of 4' x 2' and remark "bright loose group in very dense nebulosity."
Photo Index by Jim Lucyk: Sky&Tel. 2/61 p74.
The RNGC (Sulentic and Tifft 1973) notes that this is a cluster+nebulosity in the LMC.
ASV Journal Vol 24 No 3 June 1971: "seen in 6-inch."
IC 2115; IC 2116
15cm - lgst of neb in N1761 grp, 5'x3' in pa60 w/strong UHC and mod [OIII] enhancement. sup cl has 20 *s m12+ w/one V=11.4 at NE end. *s are strung along S-facing flank of neb. WSW end of neb has semi-detached approx circ portion. BS, 11Nov1993, LCO.
Location: Pietersburg South 23o 53. East 29o 28.
Sky conditions: Clear.
Date: 4 Julie 1997.
Field of view: 52.7 arc minutes.
ASSA-DSO - Report J
Extended dark, irregular, uneven nebula. The area in and out this barshape nebula is shattered with bright stars. Patches of nebulism in the field of view.
(8-inch Meade, 18mm Super-Wide Angle eyepiece, 36' fov)
Three very bright irregular gas clouds fill a nearly full field triangle (18mm eyepiece). The cloud to the west contains a cluster of clear stars. The smallest blob to the north, with a larger roundish cloud to the south. A dusty field, which is very impressive.
12-inch f/10 SCT (EP: 2-inch 40mm SW 76x 53' fov; 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov)
In the midst of the LMC three very bright irregular gas clouds nearly fill the field of view (76x). To the west the oblong dark cloud contains a cluster of a few 11th magnitude stars. The smaller blob to the north is just visible, and the larger round soft cloud can be located in the south. The dusty field of view is quite impressive.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
This open cluster with its nebula consists of 13th magnitude stars which make this cluster well detached and that most of the stars in this cluster are nearly as bright as each other.The stars in this cluster is slightly concentrated towards each other and I have noticed that this cluster is embedded with nebulosity around the stars in this cluster giving this open cluster a misty haze appearance and that this cluster is arranged in the letter of an S.This open cluster measures 7.1'x 5.4'.
The Messier objects
The Bennett objects
The Caldwell list
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