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M13 in Hercules


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Scope: Celestron 9.25 Edge 235 mm at f/10, Location: Laguna Mountains, CA  3  May 2013  Camera: ST8300M

Exposure: 11 x 6 min  (1x1 bin) exposure with UV/IR block, 8 x 2 min (2x2 bin) RGB exposures.

Processing: Data Collection -  CCDSoft (as FITs).  Calibrated, stacked (Sigma Combine), LRGB channel registration, central gradient removal, and color equalization - Astroart.  Curves, Levels, LRGB combine and finishing  - Photoshop.  Color calibration using eXcalibrator. This image is a LRGB combine with Luminance layering -   Final Image size is approximately 2400x1813.

North is up in this image.  M13 is one of the most prominent and best known globulars of the Northern celestial hemisphere. It  is one of the more outstanding globular clusters - it contains an estimated several 100,000 stars and is estimated to be about 25,100 light years distant. According to Kenneth Glyn Jones, M13 is peculiar in containing one young blue star, Barnard No. 29, of spectral type B2 (I believe it can be seen in this image in the lower right of the globular disc). The membership of this star was confirmed by radial velocity measurement, and is strange for such an old cluster - apparently it is a captured field star. This image replaces an earlier image that can be seen in the Archives here. Horizontal FOV is 26'

Image center is approximately - Equatorial 2000: RA: 16h 41m 42s Dec: +3627'39"


All images and content remain the property of Jim Thommes - copyright 2003 - 2013

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