SaratogaSkies Jim Solomon's Astropics


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M42 (The Great Nebula in Orion)   [obsolete]

Image Details:

Camera: Mofidied Canon Digital Rebel (300D): Hutech (no filter)
Mount: Celestron AS-GT
Scope: Orion ED80 (80mm f/7.5 APO Refractor)
Configuration: Focal Reduced
Additional Optics: Celestron F/6.3 Reducer/Corrector (0.63x)
Filter: None
Effective Focal Length: 420mm
Effective Focal Ratio: f/5.2
Exposure: 16 x 4min, 15 x 30sec @ ISO 200
Total Exposure: 1hrs, 11min
Date: 2/28/2005, 8:31:23 PM PST (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, cropping
  • Photoshop: Compositing, levels, image scale, JPG conversion

Image Description:

This is a new image of M42, captured almost one year to the date after catching the astrophotography bug with this old image of M42. This is also my first image taken with a modified Digital Rebel. For this I used fellow Saratogan Rich Schuppert's camera (Thanks Rich!) which has been modified to remove the IR blocking filter. That filter blocks much of the red H-alpha color in emission nebulae. See the old image for comparison, even though, well, there's really no comparison between this new image and the old one. <g> The transparency was pretty poor the night this was shot, but the Modified Digital Rebel did a great job of capturing the H-alpha.

The objects in this image are as follows (left to right):

  • NGC 1981, Open Cluster
  • NGC 1977, Open Cluster and "Running Man" Nebula
  • M43, Bright Nebula
  • M42, The Great Nebula in Orion
  • NGC 1980, Open Cluster

Together these objects make up the "sword" region of the constellation of Orion (imagine this image rotated 90° clockwise), which looks like a fuzzy blur to the naked eye but looks stunning in binoculars or almost any telescope.

There was a bizarre anomoly in the original image which I removed using the clone tool in Photoshop. Need to run down the cause of that.

Update: The cause was an internal reflection off of the ADPT2THREAD adapter I used between the ED80's 2" socket and the Celestron focal reducer. Replacing that with the barrel half of an Orion 2" T-adapter removed the problem.

North is to the left.