SaratogaSkies Jim Solomon's Astropics


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M20 (Trifid Nebula)

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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: 17 x 4min @ ISO 400
Total Exposure: 1hrs, 8min
Date: 8/29/2005 9:03:35 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
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Photoshop: Levels, cropping, JPG conversion

Image Description:

This is a "do over" of M20, the Trifid Nebula, in the constellation of Sagittarius. The Modified camera did an excellent job at capturing the Hα (deep red) color in the nebula, while also capturing the blueish/greenish tones in the reflection nebula. My previous attempt at M20 is still available, that one with an unmodified camera. This is the full frame, shrunk for display on the web. A full-resolution image is also availble. North is up.