Complete Observers Challenge Report: AUGUST 2013 OBSERVERS CHALLENGE – NGC-6791

• Date: August 26,  2013
• Time: 11:00 PM EDT
•  Location:  Foothills of North Carolina
•  Naked Eye Limited Magnitude:  5.0 
•  Temperature:  60’s and humidity:  90%
•  Both Seeing and Transparency:  Fair  
•  Telescope:  10-inch f/4.5 Newtonian 
•  Magnification:  44x  Field of View:  1.3º 

     NGC 6791 is a faint and difficult open cluster from my moderately light polluted backyard.  

     I had read various observing reports describing the beauty of this cluster.  One observer said “a glorious sprinkle of over three hundred stars.”  

     However, for me, it’s extremely difficult, but once found, it is indeed a beautiful cluster.    

     The cluster appeared as a very faint glow with a somewhat elongated shape, oriented N-S.  I could count about eight fairly bright stars, but in the darkness behind these stars is a sprinkling of maybe 35 very faint stars.  Averted vision was required, and the faint stars of the cluster seemed to sparkle.  What a beautiful sight!  The fainter stars seemed to be far in the distance behind what I perceive as foreground stars.  

      The most noticeable feature is a chain of three brighter stars on the SW edge of the cluster.  The middle star in the chain has a fainter companion, which makes a total of four stars, but this additional star required at least 100x to see.  I can now easily locate this cluster by looking for this small star chain.  

      The following sketch was made using a blank 5 x 8 note card, and a No. 2 pencil.  The colors were inverted using my scanner.

Roger Ivester

The following image is by Dr. James Dire from Hawaii.  

Complete Observers Challenge Report: AUGUST 2013 OBSERVERS CHALLENGE – NGC-6791