NGC/IC Project Restoration Effort
(This is a very very beta version)
NGC3550
Basic Information
Location and Magnitude
Right Ascension: 11:10:38.3
Declination: +28:46:4
Constellation: UMA
Visual Magnitude: 13.2
Historic Information
Discoverer: Herschel W.
Year of discovery: 1785
Discovery aperture: 18.7
Observational
Summary description: F (? Var), S, R, bM, * 9 f 1', 1st of 4
Sub-type: E-S0
Corwin's Notes
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NGC 3550. I've been curious for some time about this galaxy, called a
"double nebula" in CGCG. The object actually looks triple in the DSS image --
or are those superposed stars? I have wanted to examine it on one of the
digital sky surveys.
Finally, the SDSS has covered the area. While the two objects to the north
are certainly galaxies, the southwestern component is quite stellar. However,
2MASS has three acceptable images in its three bands. It appears that all
three objects are galaxies. This is confirmed by the redshifts given by John
Tonry in AJ 90, 2431, 1985 (cz = 11000 km/s for the faint southwestern galaxy,
10447 km/s for the central galaxy, and 10388 km/s for the northeastern galaxy;
all the redshifts have errors of +- 15 km/s).
I have, by the way, taken the object closest to the middle of the entire
image as NGC 3550. It may be better to take a mean position for the entire
triple object.
Note, too, that both JH and Dreyer have notes discussing possible variability
of the galaxy. As Dreyer concludes in 1912 in his edition of WH's papers, the
only really outstanding brightness estimates suggesting that come from JH
himself: His six observations run from "B" to "eF". All the other visual
observations suggest "vF" or "F". There is no hint in the modern literature
of any of the galaxies being a Seyfert, nor have there been any observations
suggesting the existence of a supernova remnant in NGC 3550. JH probably had
to contend with variable seeing and a speculum mirror of variable condition.
Also see NGC 3552 where this figures in the NGC identification problems in
Abell 1185.
Steve's Notes
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NGC 3550
13.1" (3/24/84): brightest in the AGC 1185 cluster. Faint, small, round. A mag 11 star is 1.5' E and a mag 12 star 1.5' SSW. NGC 3552 lies 4.7' SSE.