NGC 6229

Globular Star Cluster in the Constellation Hercules

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Globular cluster NGC 6229 was discovered by William Herschel on May 12, 1787, and first taken for a planetary nebula from his visual impression. Thus he cataloged it as H IV.50. John Herschel apparently never observed it, and Admiral Smyth also saw it as a nebula, and mentions that tt was taken for a comet in 1819. William Huggins found its spectrum to be continuous. It was only revealed as a "very crowded cluster" by d'Arrest in the mid 19th century. Dreyer's NGC lists it as globular cluster.

The difficulty to resolve this cluster becomes reasonable when looking at its large distance of about 100,000 light years from earth.   NGC 6229 is approximately 130 light years in diameter. 

Image Information  Courtesy of  SEDS

Image Details:

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  • Instrument:  Planewave Instruments CDK 12.5 f/8 OTA with Astro-Physics AP27TVPH focal reducer @ 2000mm focal length.
  • Mount:  AP1200GTOCP3
  • Image Scale:  1.2 arc-seconds per pixel after processing
    Camera: SBIG ST-2000XM with AO8 Adaptive Optics and CFW10 Color Filter Wheel using Custom Scientific LRGB filters 
    Filters & Exposure Times:
    • L:  6 x 5 minutes binned 1 x 1
    • R:  6 x 5 minutes binned 2 x 2
      G:  3 x 5 minutes binned 2 x 2
      B:  5 x 5 minutes binned 2 x 2
    • Multiple Luminance Layering in Photoshop (technique as described by Rob Gendler)
    • Total equivalent unbinned exposure time of 2.8 hours
    Software: Maxim DL/CCD, CCDStack, Adobe Photoshop CS2, RC Astro Gradient X-Terminator
    Location:  C.A.A.S. East Observatory, Little Rock, AR., El. 650ft
    Date: May 31st, 2011

Wade Van Arsdale
Little Rock, AR., USA
June 5th, 2011