NGC 2311 (Lund 276, Cr 123) Open Cluster in Monoceros

Located at: RA 06 hours 57 minutes 48 seconds, Dec -04 degrees 36 minutes 42 seconds

Size: 6.0' (7.0') Magnitude: 9.6 Class: III 2 m

North is up

West to the right


 8" f5 Newtonian reflector


 ST-8XME, self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.56


Lumicon Red filter, 450 minutes (45 x 10 minute subs), 03/5/8/2011; seeing 2.2-4.8 FWHM per CCDStack


CCDStack 2.19.4070.268047, Photoshop 7.0


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


This image is a re-shoot of a 03/2007 red-filtered 100 minute exposure ... had a hazy, moon lit sky, and some poor seeing for this image.

According to "Star Clusters", by Brent Archinal and Steven Hynes, the size of this open cluster is 7.0 arc minutes.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 2311

NGC 2311 = Cr 123 = OCL-553 = Lund 276
06 57 48 -04 36.7
Size 7

17.5": three dozen stars mag 11-15 in 5'x2' region elongated ~N-S.  Fairly rich 
though no dense spots.  Most stars form a thin isosceles triangle with the 
vertex star mag 13 at the N end, although the brightest star is a wide double 2' 
ESE of the vertex.  From the base of the triangle a stream heads SE and then E 
from the cluster mixing with some brighter field stars.  The cluster includes a 
few close faint double stars.

- by Steve Gottlieb