NGC 6633 (Lund 834, Cr 380) Open Cluster in Ophiuchus

Located at: RA 18 hours 27 minutes 13 seconds, Dec +06 degrees 30 minutes 37 seconds

Size: 27' (20') Magnitude: 4.6 Class: III 2 m

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 4.54

Image:

 Red (Hoya 25A) filter, 100 minutes (10 x 10 minute subs), 08/4/2006

Processing:

MaxIm DL 4.56, CCDStack 1.1, Photoshop 7.0

Location:

Rolling Roof Observatory, Thousand Oaks, California 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 20 arc minutes.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6633

NGC 6633 = Cr 380 = Mel 201 = Lund 834
18 27 15 +06 30.5
V = 4.6;  Size 27

13.1": very bright, very large but loose and scattered.  At 62x, 150 stars are 
visible in a 60' field with several bright stars on the SW side and many bright 
stars are outside this field including mag 5.5 SAO 123516 15' SSE.  This is a 
naked-eye open cluster in dark skies.

- by Steve Gottlieb