SOCO IMAGE GALLERY


 

NGC 6791      

NGC 6791 is an open cluster lying in the stream of the Summer Milky Way along the eastern edge of the constellation Lyra. While not visually impressive, this cluster is known for its great age. With an estimated age of 8 billion years, it is one of the oldest known open clusters in the Milky Way galaxy. It is one of the most "metal-rich" open clusters, meaning that most of its stars have a relatively high concentration of elements heavier than hydrogen. This would be expected for stars late in the atomic fusion process. Most of the stars in the cluster have already departed from the "main sequence" of stars which contains younger stars like our Sun. The cluster contains groups of white drarf stars that are some of the dimmest members of the cluster. These characteristics have led some to speculate that NGC 6791 might be a sparse globular cluster rather than a rich open cluster.
NGC 6791 contains around 380 member stars spread across a visual area with a diameter of 10 arc-min. The cluster has a visual magnitude of 9.5, but it tends to be a bit lost in the richness of the surrounding Milky Way stream. The cluster lies at a distance of around 13,300 LY.
To the lower left of the cluster in my image is the bright red carbon star TYC 3134-1708-1 (also known as V* U Lyr). This magnitude 10.2 spectral class C4 star is late in its stellar lifetime. As a result of the atomic fusion process, it now contains more carbon than hydrogen. This abundance of carbon in the stellar atmosphere gives the star its bright red color. Carbon stars may eventually give rise to planetary nebulas.

Date(s) Acquired: 8 September 2016
Telescope: Orion 120mm EON Apochromatic Refractor
Camera: QSI Model 583

 

   Exposure Time (min) 
   Number of Exposures
   RGB
   1.5
   
   -
   
   -
   OIII
   -
   RGB
   16
   
   0
   
   0
   OIII
   0

 

Processing:
Master red, green, and blue images created using SuperSIAM.
Color composite image created using Basic Processing Procedure III.
Color composite image contrast-stretched using Adobe Photoshop.




 

 

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