SaratogaSkies Jim Solomon's Astropics


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M13 (Great Cluster in Hercules)   [obsolete]

Click to see high-res version.

Image Details:

Camera: Mofidied Canon Digital Rebel (300D): Hutech (no filter)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Negative Projection (Barlowed)
Additional Optics: TeleVue 2x Barlow
Filter: None
Effective Focal Length: 2250mm
Effective Focal Ratio: f/11.1
Exposure: 30 x 1min @ ISO 1600
Total Exposure: 0hrs, 30min
Date: 6/4/2005 10:34:53 PM PDT (start)
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: Manual
Guiding: GuideDog via Philips ToUcam Pro II (840k) through Orion ST80 w/ Celestron 2x "Kit" Barlow


  • IRIS: Dark subtraction, Flat field, Best frame selection, Registration, Gradient removal
  • JimP: Kappa-Sigma stacking, White balance, ASINH stretching
  • Photoshop: Levels, cropping, JPG conversion

Image Description:

This is the Great Cluster in Hercules, aka M13, a showcase globular cluster for stargazers in the Northern Hemishpere. This was taken on the same night and with the same lousy conditions as this M57 image. See that writeup for more details on the conditions and the processing.

For this image, I used fellow Saratogan Rich S.'s modified 300D (Thanks Rich!), though the modified camera probably didn't make much of a difference with this particular object. Check out my previous attempt at M13 for a comparison. This is the full frame, shrunk for display on the web. The full-resolution image is also available. North is up.