The Double Cluster in the constellation Perseus

The Double Cluster in Perseus is a beautiful rich-field of two open clusters, NGC 869 and NGC 884.  The two clusters both lie at a distance of 7500 light years.  NGC 869 has a mass of 3700 solar masses and NGC 884 weighs in at 2800 solar masses; however, later research has shown both clusters are surrounded with a very extensive halo of stars, with a total mass for the complex of at least 20,000 solar masses.  Based on their individual stars, the clusters are relatively young, both 12.8 million years old.  In comparison, the Pleiades have an estimated age ranging from 75 million years to 150 million years. There are more than 300 blue-white super-giant stars in each of the clusters. The clusters are also blue-shifted, with NGC 869 approaching Earth at a speed of 39 km/s (24 mi/s) and NGC 884 approaching at a similar speed of 38 km/s (24 mi/s).^[

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Image Details:

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    • Instrument: Stellarvue SV130EDT triplet apo refractor:  130mm aperture, f/7 focal length (910mm)
      Mount: Paramount MX by Software Bisque
    • Image Scale:  3.5 arc-seconds/pixel after processing
    • Camera: SBIG STL-11000M CCD camera
    • Filters:  Astrodon I-Series LRGB using integrated STL filter carousel
      Exposure: Luminance: 12 x 5 minutes binned 1 x 1, using Hutech IDAS LPS-2 LPR Filter
                        Red:  6 x 5 minutes binned 2 x 2
    •                   Green: 6 x 5 minutes binned 2 x 2
    •                   Blue:  6 x 5 minutes binned 2 x 2
    •                   Total equivalent unbinned exposure time of  4 hours

      Capture Software: Maxim DL/CCD
      Processing Software:  CCDStack, Adobe Photoshop CS2

      Location:  CAAS East Observatory, Little Rock, AR., USA, el. 650 ft
      Capture Dates: November 22nd-24th, 2013

Wade Van Arsdale
Little Rock, AR., USA
December 12th,  2013