M46 and M47

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M46 and M47
  • RA: 07:41.8 and 07:36.6
  • Dec: -14:49 and -14.30
  • Magnitude: 6.0 and 5.2
  • Distance: 5400 ly and 1600ly
  • Constellation:  Puppis
  • Scope: Orion ED80 at f/7
  • Autoguider:  ST-4 in faint mode
  • Sky conditions:  Average seeing and transparency with a low in the 20s.
  • Camera: Hap Griffin modified Canon XSi at 800
  • Exposure:  10 x 2 minutes
  • Date:   March 10, 2011

Comments:  M46 was the first object Charles Messier discovered after publishing the first edition of his list.  It was added to the catalog on February 19, 1771.  The cluster is very rich, with 150 stars of magnitude 10-13 and probably a total population of over 500.  The cluster is about 300 million years old.  A feature of interest that is in the field of view is the planetary nebula NGC2438.  The derived distance of the nebula is about 2900 light years which would indicate that it is a foreground object. The open cluster M47 was discovered in 1654 by Hodierna.  It is a bright cluster which can be glimpsed with the naked eye under good conditions as a dim nebulosity.  It is a course cluster of bright stars, and contains about 50 stars in a region 12 light years in diameter. The open cluster NGC2425 can be seen in the lower middle of the image. The open cluser NGC2423 can be seen at the top right of the image.