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Type: bright nebula
Mag: B=?, V=?
Size: 20′ x 20′
IC 2177. The IC position, claimed to have been taken from Isaac Roberts's short note in AN 3509, is not from that note. Roberts's position is for BD -10 1848 and the HII region surrounding it, and that is the position that I've adopted in the table. Roberts copied it correctly from the BD into his note, but the IC position points to a bit of non-descript space about 20 arcmin southeast of the HII region.
There is an additional reference to this nebula in Wolf's note "Extended Nebulosities" in AN 4082, though Dreyer did not include that as a source for this object in the IC. Wolf notes that the nebula covers "many square degrees" and stretches at least from Roberts's nebula in the north on south to BD -12 1771.
Wolf's description of this large star-forming region is fairly good as far as it goes. The brightest, largest nebula is indeed Roberts's, but Wolf found the 2.5-degree long S-shaped nebula to its south and east. This actually extends a bit more faintly at least another 2 degrees east from its northern end, but Wolf apparently did not photograph that portion of it. NGC 2327, a small compact nebula, probably also an HII region or at least a part of one, is embedded in the sinuous nebula south of I2177.
I suspect that Dreyer was somewhat influenced by Wolf's description, so decided to give it some weight, but tried to retain Roberts's data as the main source for this object. This would account for the position southeast of the center of Roberts's object. So, I've simply gone back to his data for the main position for I2177. Given that Wolf's note is pretty accurate, though, I've also included the approximate center of gravity of his much larger S-shaped nebula under same number with a directional subscript.
The entry in the IC credits discovery to Roberts, who found it photographically. The description reads: "pretty bright, extremely large, irregularly round, very diffused." This would make the nebula at least 20' in size.
Roberts, I. (1898) "Nebulae which are not recorded in the Catalogues, found upon Photographs by Isaac Roberts, D.Sc., F.R.S." A.N. 3509.
Detailed for the first time in this publication.
Notes on southern nebulae. Transvaal Observatory Circular, No.7, 76.
Ced 89c (IC 2177)
Position (1900): RA 7 0.4, Dec - 10 33
Star: -10 1848 (Mp=7.3, V=7.1, SpT=B0p)
Spectrum of nebula: emission spectrum (observed)
Classification: Neb associated with mainly one star (which may be multiple) - Fan-shaped object (eg. IC 59)
Notes: "Ced 89 The nebulous region of IC 2177. Ced 89 c = IC 2177. Disc. Roberts 1898 (611). FA 75. (216, 366, 614, 630 Pl 37, 89 715, 812, 829)."
Colin S. GumA Survey of Southern H II Regions published in the RAS Memoirs, Vol. LXVII, tentatively identifies his No. 1 with IC 2177. He notes, however, that the accuracy of the NGC positions are not sufficient to prevent confusion with NGC 2327. He describes the nebula as a diffuse emission nebula, roughly circular and measuring 15'. He rates the intensity, or "visibility in the particular section of the Milky Way in which the object occurs" as "bright" on a scale of vf - f - mb - b - vb. He lists HD 53367 (pmag. 6.8) as the exciting star. In his scheme of classifying the large-scale structural features of nebulae, the nebula is rated a 3, which corresponds to "an almost uniformly bright circular disk with the exciting star at the geometrical centre."
The catalogue of southern emission regions by Rodgers, Campbell and Whiteoak (1960) lists as RCW 2 a bright nebula, 14' x 14' large, which they identify with IC 2177 and Gum 1. They describe it as a "circular, connected to [RCW] 1 by faint emission."
Lynds, B.T. (1962) Catalogue of dark nebulae. Astrophys.J.Suppl.Ser. 7, 1-52. [also: computer datafile: VII/7A]
According to Lynds' Catalogue of Bright Nebulae, published in 1965 in the Astrophysical Journal Supplement (#105), his No. 1027 is IC 2177. He describes a very bright nebula, which is brighter on the red POSS plate, and has a maximum size of 20'.
For the same star (HD 53367), van den Bergh in a catalogue of reflection nebulae (Astronomical Journal, 1966, volume 71) lists the star as being involved with a nebula, vdB 93. He states that the illuminating star is embedded in the nebulosity, which has a very bright surface brightness on the blue prints of the POSS, and appears equally bright on the blue and red prints of the POSS. Absorption in the field containing reflection is strong. The maximum radius observed on the blue print is 10' and on the red print 8.5'.
Sanford writes: "South of M50 is an interesting large nebulous region, suited to photographic rather than visual observation, although the brighter parts can be seen in an 8-inch. This is IC 2177 and its associated clusters NGC 2335, NGC 2343, and Collinder 465 & 466. There are two main parts to the nebula, a two-degree long north-south curtain of nebulosity which crosses the border into Canis Major, and the smaller eye-like vdB 93 ... This entire nebula has been given the appellation the Seagull Nebula because of the curved wings of nebulosity. Hans Vehrenberg .. calls it 'the Eagle' in his Atlas of Deep Sky Splendors. At least a 300mm lens is needed to see much detail, although it appears on a 50-mm photo by the author as a small streak with a couple of spots of nebulosity."
= VdB 93, GN 07.02.0, Other designations: Sh292
Class: C+E (emission and reflection neb)
Van den Bergh describes the object in his catalogue as being involved with the 6.97 mag star BD-10°1848 (HD 53367), which is embedded in the nebulosity. On the blue POSS prints is has a very bright surface brightness, and appears equally bright on the blue and red prints. There is strong absorption in the field containing the reflection nebula. The maximum radius observed on the blue POSS print = 10', and the maximum radius observed on the red print = 8.5'
VDB 93: Photo index by Jim Lucyk: Vehrenberg's Atlas of Galactic Neb-1 p115 (on photo with NGC 2327)
Also Stromlo 2 -- Sky&Tel. 7/79 p21, Deep Sky #5 Wi83 p27, Deep Sky Monthly 10/80 p5, Vehrenberg's Atlas of DS Splendors (3ed) p82, 83, Vehrenberg's Atlas of Galactic Neb-1 p113.
VDB 93: Sanford writes: "South of M50 is an interesting large nebulous region, suited to photographic rather than visual observation, although the brighter parts can be seen in an 8-inch. This is IC 2177 and its associated clusters NGC 2335, NGC 2343, and Collinder 465 & 466. There are two main parts to the nebula, a two-degree long north-south curtain of nebulosity which crosses the border into Canis Major, and the smaller eye-like vdB 93, a small nebula surrounding a star. There is a horizontal dust lane through this nebula which makes the whole thing look much like an eye with the pupil the star. This entire nebula has been given the appellation the Seagull Nebula..."
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "The Eagle; 2.5 degree x 0.5 degree extent; very faint streamers form the Eagle's wings which extend N and S; her head is Gum-1; at the tip of her S wing is Ced-90; use N-filter and wide field, or N-filtered binoculars; shares the name "EAGLE" with M-16; reference: VADSS-83."
Steve Coe, observing with a 13" f/5.6, notes: "is a very faint, very large, 5X1 elongated streamer of nebulosity that ends in NGC 2335 cluster. The nebula can be seen best with the UHC filter at 100X and averted vision helps quite a bit. The central part of the streamer is the brightest."
Observing site: Little Tycho Observatory
[7h 5m 6s, -10° 42' 0"] A slight brightening of the night sky, surrounding a chain of 11mv stars, filling half of the field of the 12.5mm, or about 8'. WikiSky: A nebulous patch, invisible in the light pollution. B: extremly faint.
The Messier objects
The Bennett objects
The Caldwell list
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