SaratogaSkies Jim Solomon's Astropics


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Sh 2-157 (Emission 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: Orion ED80 (80mm f/7.5 APO Refractor)
Configuration: Focal Reduced
Additional Optics: William Optics 2" APO 0.8x Reducer/Field Flattener
Filter: None
Effective Focal Length: 480mm
Effective Focal Ratio: f/6
Exposure: 28 x 8min @ ISO 800
Total Exposure: 3hrs, 44min
Date: 12/18/2006 7:02:16 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

Image Description:

This is Sh 2-157 et. al., an interesting field straddling the constellations of Cassiopeia and Cepheus. Also present is the Bubble Nebula, aka NGC 7635 (click here for my closeup shot) and NGC 7538, another emission nebula. Open Cluster NGC 7510, right, is best seen in the higher resolution image. The brighter nebulae in this shot shine through pretty well, but Sh 2-157 is very faint and needs a better night, more exposure time, and/or some Hα exposures to bring it out. Mouse over the image to see the annotations. A higher resolution image is also available. North is up.