NGC 2331 (Cr 126, OCL-475) Open Cluster in Gemini

Located at: RA 07 hours 06 minutes 59 seconds, Dec +27 degrees 17 minutes 43 seconds

Size: 18' (19') Magnitude: 8.5; Class: IV 2 m

North is up

West to the right


 8" f5 Newtonian reflector


 ST-8XME, self-guided, binned 1x1, temp -25c, camera control MaxIm DL 4.56


Lumicon Deep Sky filter, 180 minutes (18 x 10 minute subs), 01/29/2008; seeing 2.2-2.8 FWHM per CCDStack


CCDStack 1.3.2, Photoshop 7.0


 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes: According to "Star Clusters", by Brent Archinal and Steven Hynes, the size of this open cluster is 19 arc minutes.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 2331

NGC 2331 = Cr 126 = OCL-475 = Lund 295
07 07 00 +27 15.7
Size 18

17.5": at 82x, very large scattered group of about 40 stars mag 10-14, 15' 
diameter.  There is a small circle of 6 stars at the E end.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 2331
NGC 2331 is a large, scattered cluster of pretty bright stars.  There is a 
concentration of several stars on the southeast edge that attracted JH's 
attention enough that he took it as the position for the whole object.  Thus,
the position in the main table is about 8 arcmin northwest of the NGC place,
copied directly from GC and JH.

A curious footnote to this object is in the "Other Observers" column in the 
NGC:  "Flamsteed."  I do not know yet why Dreyer credited Flamsteed with the
discovery -- there is no mention of the object in Kenneth Glyn Jones's fine
book, "The Search for the Nebulae."  According to Glyn Jones, Flamsteed did 
find several other objects in the area, including M41 and NGC 2244.  But this
cluster is missing from his catalogue and atlas. - Dr. Harold G. Corwin, Jr.