NGC/IC Project Restoration Effort
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NGC2175
![](Images/negative_NGC2175-ngcicproject.jpg)
Basic Information
Location and Magnitude
Right Ascension: 6:9:38.6
Declination: +20:29:18
Constellation: ORI
Visual Magnitude:
Historic Information
Discoverer: Bruhns
Year of discovery: 1857
Discovery aperture:
Observational
Summary description: * 8 m in neb (Auw No 21)
Sub-type: EN
Corwin's Notes
=====
NGC 2175 is a very large roughly circular emission nebula which also includes
NGC 2174 and IC 2159 (both of which see), and a star cluster which has
inherited the NGC number, though there is no mention of it in the discovery
notes. The nebula is centered on SAO 078049, though the brightest knot (which
Bigourdan took for N2175; hence, the "corrected" RA in the IC2 Notes) is
about three arcmin to the west-northwest. Auwers's note makes it clear that
NGC 2175 is much more than just the knot: he gives dimensions of 25 arcmin by
8 arcmin, and specifically adopts the position of Lalande 11668 = SAO 078049
as that for the object. I have followed his lead.
Note that Archinal and Hynes in "Star Clusters" call out another smaller
cluster as "NGC 2175.1". This is a small group of about a dozen stars at
06 10 53, +20 36.6 (J2000) no more than five arcminutes across. They
correctly point out that this has nothing to do with the NGC object -- the
nebula -- and suggest deprecating the NGC number often attached to this group.
I agree, so have not put this object in the main table, but do note that
Collinder 84 is associated with the nebula. Archinal and Hynes have some
doubts that this is a real cluster, but Brian Skiff has it centered on the
same star that Auwers chose. Archinal suggests reserving the NGC number
strictly for the nebula, but if the stars are associated with it, I see no
reason not to adopt the NGC number for Collinder 84 as well. We (observers
over the centuries) have done this with, for example, M 17 = NGC 6618 and M 42
= NGC 1976 with little or no confusion, so doing the same here should not be a
problem -- as long as "NGC 2175.1" is indeed dropped.
Steve's Notes
=====
NGC 2175
17.5": See description for NGC 2174. Although the scattered group of stars involved with the HII region is identified as NGC 2175, the NGC description (from Auwers and Bruhns) does not refer to a cluster but rather a "*8m in neb (Auw No 21)". The position given is 10' S of NGC 2174 and 16 tsec east. But in the IC 2 notes and correction, Dreyer gives a correction in RA from Bigourdan to 06 01 32. This places NGC 2175 at 06 09 52 +20 29.1 (2000) and is just 1' S of the brightest section of the nebula (about 3' ENE of mag 8 SAO 78049). The scattered group is catalogued as Cr 84.