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NGC 2244 = NGC 2239, which see.
This open cluster has as its brightest star the 6th mag 12 Mon, but is quite likely a foreground star. Sky Catalog 2000 lists it as having about 100 stars and a total mag of 4.8 However, the cluster was missed by Messier in the 1700's but was picked up by William Herschel towards the end of that century. With an estimated age of 3 million years, the cluster is still ensconsed in its nebulosity, which presents a real challenge. The Rosette nebula [NGC 2237], as it is known, is seen more easily with nebular filters.
Rosette: NGC 2244, NGC 2237, NGC 2238 & NGC 2246.
Synonyms: H VII-002
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a beautiful cluster of scattered stars, chiefly of two sorts. The first large, the second arranged in winding lines; contains the 12th Monoceros."
Ced 76b (NGC 2244)
Position (1900): RA 6 27, Dec :+ 5
Star: cl (Mp=5.3, , SpT=O6,O8,)
Spectrum of nebula: emission spectrum (observed)
Classification: Nebulous cluster (Nebulous envelop of intricate structure, eg. NGC 2175)
Notes: "76 b = The nebulous cluster NGC 2237, 2239, 2244. R. In 1857 Swift discovered a brighter patch of this nebulosity, which is catalogued as NGC 2237. The cluster was discovered by William Herschel in 1784. It is listed as NGC 2244 = GC 1424 = H VII 2. The designations : NGC 2239 = GC 1420 = h392 refer to the star 12 Monocerotis, which is a member of the cluster. The NGC positions of 2237 and 2239 are erroneous. The outer nebulosities were discovered by Barnard in 1883. WP 105. (15, 29, 30, 44, 45, 54, 55, 64, 66, 88 Pl 26, Pl 27, 114, 143, 191, 194, 208, 216, 280, 284, 294, 304, 365, 366, 478, 482, 554, 578, 613, 615 Pl 27, 622, 629, 630 Pl 35, 631, 715, 733, 753). HD stars involved or aligned : +4 1291 = HD 46056. +5 1279 = HD 46106. +5 1278 = HD 46107. +5 1281 = HD 259105. +5 1282 = HD 46149. +5 1283 = HD 46150. +5 1287 = HD 46201. + 5 1286 = HD 46202. +4 1302 = HD 46223. +4 1304 = HD 46241."
Minkowski, R. (1949) The diffuse nebula in Monoceros. P.A.S.P., 61(361), 151.
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 27' and the class as 4 3 mN.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part II. M.N.R.A.S., 35(8), 280.
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
Vorontsov-Velyaminov, B. (1925) "Catalogue of integrated magnitudes of star clusters", Astron. Nach. 226.195. Comparing the brightness of the cluster with the extrafocal images of stars, he estimates the magnitude as 6.18.
"A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.
"cluster with bright and dark nebulosity around 12 Monocerotis." He gives the approx. diameter as about 1 degree.
Sanford notes that "the Rosette can be seen as a soft glow surrounding the distinctive parallelogram of the cluster in 20x80 binoculars or a rich-field telescope."
by Jim Lucyk: Sky&Tel. 1/81 p25, Sky&Tel. 2/85 p181, Sky&Tel. 2/76 p141, Sky&Tel. 3/80 p265, Sky&Tel. 4/73 p208, Sky&Tel. 12/81 p557, Sky&Tel. 3/88 p248-9, Astronomy mag. 4/86 p60, Astronomy mag. 4/82 p16, 17, Vehrenberg's Atlas of Galactic Neb-1 p97, 98, Astronomy mag. 6/75 (back cover), Astronomy mag. 7/76 p78, Deep Sky #6 Sp84 (back cover).
It forms part of the Monoceros OB2 association.
The RNGC (Sulentic and Tifft 1973) notes that this is a 5.0 mag cluster associated with nebulosity.
MacRobert writes that this cluster "is bright and easy in binoculars or a finder and lovely indeed in the 6-inch. Its six leading stars form a rectangular box shape that can be recognized at a glance in any instrument. Others scattered about give the impression that we have opened the door into a rich nest of suns ... the cluster is the heart of the Rosette Nebula..."
Ken Reeves, in "SACNEWS On-line for March 1997", observing with a 10-inch f/4.5 scope, notes: "NGC 2244 (06 32.4 +04 52), also NGC 2237, 2238, 2239, and 2246. This group of clusters and nebulae is the Rosette Nebula, 2244 and 2239 being the cluster and 2237, 2238, and 2246 being the nebula. Use low power when looking at this object. At 35x I saw the cluster as pretty bright, very large, very loose, not at all rich, with 15 stars in 3 levels, including a fairly bright yellow star. I also observed a starless area to the W of the cluster. This was the only indication I had of the nebula without the filter. However, when I used the UHC filter, the nebula really jumped out. The starless area to the W of the cluster is the largest area, grey without any detail. To the E and SE the nebula is smaller, but much more detailed including many dark areas. This is definitely one of the beauties in Monoceros."
Listed by the Herschel Club, described as "very large and bright, very loose grouping of stars, some 16 stars counted. 6-inch, 48x."
Harrington writes: "Binoculars will immediately reveal the group's half-dozen brightest stars in a distinctive rectangular shape. Most brilliant is the 6th mag 12 Mon, a yellowish sun contrasting with a nearby blue-white star."
Observer: John Callender
Instrument: 50-mm binoculars Location: Carpinteria, CA, USA
Light pollution: light Transparency: good Seeing: fair
Time: Wed Feb 5 04:50:00 1997 UT Obs. no.: 50
A mini-parallelogram of 6 faint stars, visible to the naked eye as a faint patch in averted vision. Very pretty in the 7x50s. I almost didn't record it in my list, thinking it might be too sparse to be a charted cluster; only afterward did I discover it was the cluster at the heart of the Rosette Nebula.
Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA
Light pollution: light Transparency: good Seeing: poor
Time: Sat Mar 1 05:35:00 1997 UT Obs. no.: 90
Spent just a few minutes examining the cluster at the heart of the Rosette Nebula at 48x, looking for traces of nebulosity. Didn't see any.
Steve Coe, observing with a 13" f/5.6, notes: "is the star cluster involved in the Rosette. In the 13" at 60X it consists of 2 parallel lines of about 15 stars. It is very bright, very large and not compressed. Several of the stars are yellow and one is a lovely orange. On the best of evenings, this area is a bright spot in the Winter Milky Way to the unaided eye."
Observing site: Pinnacles overlook
[6h 32m 24s, 4° 52m 0s] A large cluster in a rich region. The famous "Rosette nebula" was lost in the sky glow.
Instrument:12-inch Dobsonian Reflector Telescope.
Sky Conditions:The fainter parts of the Milky Way are barely visible.
Transparency Of the Sky:Haziness only visible on the horizon.
Seeing:Atmosphere stable with little interference.
The stars in this cluster are not at all concentrated and have the appearance almost like a star cloud.However this cluster consists of 5th to 8th magnitude stars and this cluster is not separated from each other.This cluster however has bright and faint stars mixed together.The whole cluster is equally bright right to the far outskirts of this cluster. It measures 11.2'*2.8'.
Object: NGC 2244
Observer: Carol Botha
Date & time: 2015.01.21 / 22:30
Location: Betty’s Bay
Instrument: 12 inch Dobsonian F5. Binoculars 10x50
Eyepiece: 25mm plossl (fov 50')
Sky: Clear. Some light pollution E horison
Limiting mag: 5.55 HD59256
Quality: Very windy. Observing with shade netting shelter
Open cluster in Monoceros.
Binoculars: Through binoculars the faint Monoceros comes to life. A comfy recliner would come in handy here. I’ve seen by the by that the pronunciation is actually ‘muh-NAH-ser-us’. Finding this target is surprisingly easy (even if the dog has eaten your star charts) by using familiar stars in the vicinity as guides. Scan down an imaginary line between Betelgeuse and Procyon. Stop a third way down the line and change direction towards Sirius. You will not miss the almost rectangular tight grouping of stars, just off the ‘highway’. Very pretty.
25mm: A sparse open cluster. One bright yellow star S, a few medium bright and a few dim but pretty doubles form two parallel lines. N of the cluster just inside FOV is a very bright star. Having located this cluster, I realize that the Rosetta nebula resides here as well but much more challenging to observe.
The Messier objects
The Bennett objects
The Caldwell list
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