NGC 1647

Observation Notes:

I first noticed NGC 1647 between the horns of Taurus in a wide-field astro photo I shot of the area in November 2005. I’ve been meaning to observe and sketch it since then. At 37.5X magnification, the cluster appeared large, bright and sparse. Two colorful yellow and yellow-orange stars rested at the south side of the cluster. I noted several doubles within. The diameter of the main body of the cluster appeared to be about 30 arc minutes.

Several bright Orionids graced the sky and caught my attention during the observation and sketch. Dave Saunders and I noted one meteor trail that lasted over 30 seconds. Nice!

Object Information

NGC 654 was discovered by Friedrich Wilhelm Herschel in 1784. According to Catalogue of open cluster parameters from UBV-data. (Loktin+, 1994), the cluster is about 509 parsecs distant (1,660 light years). Star Clusters and Associations, Selected Data (Alter+ 1970) lists a distance of 550 parsecs (1,790 ly). The cluster is also catalogued as Cr 54, Mel 26, OCL 457, Lund 139, H VIII-8, GC 896.

Subject NGC 1647
Classification Open Cluster (II 2 r)
Position* Taurus [RA: 04:45:55.6 / Dec: +19:06:42]
Size* 45′
Brightness* 6.4 vMag.
Date/Time October 21, 2006 – 11:05 PM
(October 22, 2006 – 06:05 UT)
Observing Loc. Cinder Hills Overlook, Sunset Crater National Monument, AZ
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 32 mm (37.5X)
Conditions Clear, Calm
Seeing 6/10
Transparency Mag 6.8+ NELM
*Sources NGC/IC Project

*Based on published data.