SaratogaSkies Jim Solomon's Astropics


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M51 (Whirlpool Galaxy)   [obsolete]

Click to see high-res version.

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Prime Focus
Additional Optics: Celestron/Baader Multi Purpose Coma Corrector (MPCC)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 31 x 4min @ ISO 400
Total Exposure: 2hrs, 4min
Date: 5/11/2005 11:28:24 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, registration, gradient removal
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Neat Image: Noise reduction
  • Photoshop: Levels, cropping, JPG conversion

Image Description:

One of my favorite galaxies, this is M51, the Whirlpool Galaxy in the constellation of Ursa Major. M51 is the main, large galaxy, which can be seen to be interacting with the smaller NGC 5195 North of it (above it in this photo). This is a crop at 75% of the original image scale. The full size image is also available. North is up.

Compare this new image, with its 2+ hours of exposure, with this previous version with only 16min of exposure, the latter of which was one of my first guided astrophotos. The nearly 8-fold increase in exposure time makes quite an amazing difference.