SaratogaSkies Jim Solomon's Astropics


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NGC 6946 (Spiral Galaxy)

Mouse-over to see annotations. (Requires Javascript) 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: Celestron/Baader Multi Purpose Coma Corrector (MPCC)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 30 x 4min @ ISO 800
Total Exposure: 2hrs, 0min
Date: 9/16/2004, ~11:10pm 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, flat field, registration, normalized Kappa-Sigma stacking, background fit, cropping
  • Photoshop: Levels, image size, JPG conversion

Image Description:

In the lower left is NGC 6946, a spiral galaxy that straddles the border between the constellations of Cygnus and Cepheus. In the upper right is NGC 6939, an open cluster in Cepheus. This is two full hours of total exposure time and is one of my best images to date. This is the full frame, scaled for display on the web. A full-resolution image is also available. North is up.

NEWSFLASH!! Supernova 2004et occurred less than 6 days after this image was taken! Mouse-over the image below to see the supernova discovery image. Note how there's absolutely no sign of that star in my image, yet six days later it's as bright as some stars in our own galaxy!