SaratogaSkies Jim Solomon's Astropics


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NGC 7635 & M52 (Bubble Nebula & Open Cluster)

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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: 45 x 4min @ ISO 400
Total Exposure: 3hrs, 0min
Date: 12/2/2005 7:34:47 PM PST (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: Levels, cropping, JPG conversion
  • Neat Image: Noise reduction

Image Description:

This is NGC 7635, aka the Bubble Nebula, and open cluster M52 in the constellation of Cassiopeia. I used shorter subexposures (4min) at a lower ISO (400) than some previous shots (8min, ISO 800) in order to prevent severe over-saturation of the bright stars in M52. It worked pretty well, at the expense of slightly less detail in the faint regions of the Bubble Nebula. It was nice to get outside and grab this shot, as the weather here has been awful and I was in danger of a complete "shutout" this cycle. A higher-resolution image is also available. North is up.