SaratogaSkies Jim Solomon's Astropics

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December: Test shots with new scopes/mounts

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Dec 3: AP1200 Arrives!

Nov 30: TMB 152/1200 Arrives!

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NGC 6888 (Crescent Nebula)

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: 20 x 8min @ ISO 400
Total Exposure: 2hrs, 40min
Date: 10/3/2005 10:12:08 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

Processing:

  • IRIS: Dark subtraction, registration, gradient removal
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Photoshop: Levels, cropping, JPG conversion

Image Description:

This is NGC 6888, aka the Crescent Nebula in the constellation of Cygnus. While the modified camera does an excellent job of capturing Hα, an object like this needs addition Hα-only exposures to improve the contrast against its busy background. Something for another day. A higher-resolution version of this image is also available, as is my previous attempt from last year with an unmodified camera. Note how much more Hα the modified camera records. North is up.