SaratogaSkies Jim Solomon's Astropics


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M101 (Pinwheel Galaxy)   [obsolete]

Mouse-over to see annotations. (Requires Javascript) Click to see high-res version.

Image Details:

Camera: Mofidied Canon Rebel XT (350D): Hutech Type I Filter Replacement
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: 88 x 4min @ ISO 400
Total Exposure: 5hrs, 52min
Date: 5/25/2006 11:02:17 PM PDT (start) and 5/29/2006 10:31:17 PM PDT (start)
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: GADFly 1.0.5
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
  • Photoshop: Sharpening, Levels, cropping, JPG conversion
  • Neat Image: Noise reduction

Image Description:

This is M101, aka, the Pinwheel Galaxy, a stunning spiral galaxy in the constellation of Ursa Major. For some strange reason, this version — with just shy of 6 total hours of expsoure over two nights — came out better than this old version with 32min of exposure time. <grin> I may go back and add some Hα data to this RGB image in order to bring out some of the features; namely, the areas with NGC designations which can be seen by mousing-over the image above. A higher-resolution image is also available. North is up.