M 4 (NGC 6121, GCL 41) Globular Cluster in Scorpius

Located at: RA 16 hours 23 minutes 36 seconds, Dec -26 degrees 31 minutes 31 seconds

Size: 30' Magnitude: 5.4 Class: 9

North is up

West to the right

Telescope:

 8" f5 Newtonian reflector

Camera:

 ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.53

Image:

 Red (Hoya 25A) filter, 300 minutes (30 x 10 minute subs), 06/26/30 & 07/15/2006

Processing:

 CCDStack 1.2, Photoshop 7.0

Location:

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

Notes: From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6121

NGC 6121 = M4 = E517-SC1
16 23 35.3 -26 31 32
V = 5.9;  Size 26.3

17.5": very bright, very large, 15' diameter.  Resolved into an extremely dense 
swarm of several hundred stars with many stars arranged in strings.  Appears 
fully resolved at moderate power including the distinctive bar extending N-S 
through the center.  M4 is possibly the closest GC at a distance of 5600 light-
years.

13": excellent resolution, many star lanes.  The bar through the core is 
resolved.

8": superb resolution of mag 11-13 stars.

- by Steve Gottlieb