Messier 47 or M47 (also designated NGC 2422) is an open cluster in the constellation Puppis. It has an apparent visual magnitude of 5.2 and its angular diameter is 30 arc-minutes. M47 lies at an estimated distance of 1600 light years. The Equinox 2000 coordinates are RA= 7h 36.6m, Dec= -14° 30´ which makes M47 best seen during the winter. The Messier Winter Star Chart shows the position of all Messier objects visible during that season.
The image above shows the uncropped view of M46 (lower left) and M47 (upper right) through the Takahashi E-180 Astrograph (North is up). A 3x enlargement of this image centered on M47 appears to the right. The brightest star in the cluster is of magnitude +5.7.
In spite of its inclusion in the Messier Catalog, this coarse open cluster was actually discovered by G. B. Hodierna in 1654. According to Kharchenko et al. (2005), the distance of M47 is 1600 light years and its diameter is 14 light years. It contains 117 stars and its estimated age is 30-100 million years.
Messier's Description of M47
February 19, 1771
`Cluster of stars, little distant from the preceding; the stars are greater [brighter]; the middle of the cluster was compared with the same star, 2 Navis. The cluster contains no nebulosity.'
- Object: M47
- Other Names: NGC 2422
- Object Type: open cluster
- Object Data: Apparent Magnitude = 5.2, Angular Size = 30 arc-minutes
- Object Position (Equinox 2000): RA= 7h 36.6m, Dec= -14° 30´, Constellation = Puppis
- Date/Time: 2011 Mar 30 at 03:48 UTC
- Location: Bifrost Astronomical Observatory, Portal, AZ
- Mount: Astro-Physics 1200GTO
- Telescope: Takahashi Epsilon 180 Hyperbolic Astrograph
- Camera: Canon EOS 550D (Rebel T2i) (modified with a Baader UV/IR filter)
- Field of View: 1.70° x 2.56° at 1.7 arc-sec/pixel (web version: 10.0 arc-sec/pixel)
- Exposure: 4 x 300s, f/2.8, ISO 800
- File Name: M46M47-01w.jpg
- Processing (Adobe Camera Raw): Graduated Filter, Vignetting Correction, Noise Reduction, White Balance, Curves
- Processing (Photoshop CS5): Average Images, Curves, Noise Reduction
- Original Image Size: 3454 × 5179 pixels (17.9 MP); 11.5" x 17.3" @ 300 dpi
- Rights: Copyright 2011 by Fred Espenak. All Rights Reserved. See: Image Licensing.