M 12 (NGC 6218, GCL 46) Globular Cluster in Ophiuchus

Located at: RA 16 hours 47 minutes 15 seconds, Dec -01 degrees 56 minutes 52 seconds

Size: 16' Magnitude: 6.1 Class: 9

North is up

West to the right

Telescope:

14.5" f5 Newtonian reflector

Camera:

ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.56

Image:

 Lumicon Red filter, 360 minutes (36 x 10 minute subs), 07/20/21/2014; seeing 2.3-3.7 per CCDStack

Processing:

CCDStack 2.80.5308.25197, Photoshop CS5.1

Location:

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

Notes: See the 8" version.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6218

NGC 6218 = M12
16 47 14.5 -01 56 52
V = 6.8;  Size 14.5

17.5" (7/15/99): at 220x this bright cluster is highly resolved over the entire 
disc.  Appears smaller than M10, perhaps 11'-12' diameter with a fairly well-
defined 3.5' core.  Two bright field stars are embedded in the north edge of the 
halo and a third bright star is off the following end.  A mag 10 star is also 
superimposed just off the SE edge of the core.  A number of brighter resolved 
mag 12 stars appear to be grouped into pairs and trios.  There are a couple of 
hundred fainter stars in the central 8' over unresolved haze.  The outline is 
very irregular and there are distinctive star-poor areas in the outer halo.

13": bright, large, round, very intense core with faint stars scattered over 
core.  The outer halo is highly resolved into scores of stars.  Slightly 
inferior to M10 in faint stars.

8": the outer halo is well resolved and partial resolution of the core.  There 
are two or three brighter stars in the outer halo.

- by Steve Gottlieb