SaratogaSkies Jim Solomon's Astropics


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M16 (Eagle Nebula)   [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: n/a (Prime)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 24 x 1min @ ISO 800
Total Exposure: 0hrs, 24min
Date: 7/13/2004, 11:30pm PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: None


  • IRIS: Dark subtraction, flat frame, registration, and Kappa-Sigma stacking, AF5 noise reduction (red channel only)
  • Photoshop: Color mixing, slight crop, image scale (1/4 x), JPG conversion

Image Description:

Another amazing nebula in the "summer" Milky Way in the constellation of Serpens. M16 actually refers to the open cluster of bright, white, stars just above and to the right of the center of this photo. IC 4703 is the catalog name given to the nebula in which these bright, young stars continue to be born. This is a Sigma stack of the best 24 of 64 frames. The remaining 40(!) frames showed trailing/smearing due to tracking error and other problems, so either my mount is getting worse or my scope's balance was poor. I suspect the latter. The conditions were also pretty lousy, both from a transparency and seeing perspective. The dew was out of control too. As with the M17 image, I cranked up the red a bit in Photoshop to compensate for the Digital Rebel's poor sensitivity to Hα, the main wavelength emitted by nebula such as this one. This is a slight crop of the full frame image, scaled for display on the web. A full-resolution image showing more detail is also available. North is up.