SaratogaSkies Jim Solomon's Astropics

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B33 (Horsehead Nebula)

[Hα+R G B]

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: Hutech Hα Front Filter (HA-FF)
Effective Focal Length: 480mm
Effective Focal Ratio: f/6
Exposure: 21 x 8min @ ISO 800 (RGB), 29 x 8min @ ISO 1600 (Hα)
Total Exposure: 6hrs, 40min
Date: 2/21/2006 (RGB); 12/28/2006 (Hα)
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

Processing:

  • IRIS: Dark subtraction, registration, gradient removal
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, HαRGB combination, ASINH stretching
  • Photoshop: Levels, cropping, reflection removal, JPG conversion
  • Neat Image: Noise reduction

Image Description:

This is an update of my previous Horsehead Nebula image, with nearly 4hrs of Hα exposure added to the existing RGB data. The Hα really helps bring out many of the features in this busy field.

To create the HαRGB composite, I first added some Hα into the red channel of the original RGB data, which was then converted to Hue, Saturation, Luminance. Then I used a process similar to Photoshop's “Screen” blending mode to combine the luminance of the original RGB data with the (grayscale) Hα data. This Screen-blended Luminance, along with the Hue and Saturation of the Hα-enhanced RGB image, was then converted back to RGB. This method seemed to preserve details in the non-Hα-emitting regions, provide excellent detail in the Hα regions, and preserve the colors.

A higher-resolution image is also available. North is left.

 
Saturn
SaratogaSkies Jim Solomon's Astropics

Search

Latest news

December: Test shots with new scopes/mounts

Dec 21: TMB 80/480 Arrives!

Dec 3: AP1200 Arrives!

Nov 30: TMB 152/1200 Arrives!

Links:

Saturn   [obsolete]

[Hα+R G B]

Image Details:

Camera: Philips ToUcam Pro II (840k)
Mount: Celestron AS-GT
Scope: Orion ED80 (80mm f/7.5 APO Refractor)
Configuration: Eyepiece Projection
Additional Optics: University Optics 7mm HD Ortho
Filter: None
Effective Focal Length: 3500mm
Effective Focal Ratio: f/44
Exposure: 256 frames @ 1/25s, 10fps, neutral brightness, gamma, saturation, and gain
Date: 12/24/2004, 11:18pm PST
Location: Saratoga, CA, USA
Acquisition: Philips VRecord
Focus: Manual
Dithering: None
Guiding: None

Processing:

  • IRIS: Registration, best-frame selection, stacking
  • Photoshop: Levels, Unsharp Msking, JPG conversion

Image Description:

This is my first decent planetary image using a webcam as the imaging platform. I was just playing around with my new toy -- the Orion ED80 -- and thought I'd try capturing a planetary image, since the moon was very bright and there was no chance of getting a decent deep sky image. I'm amazed at what that little refractor can do, and what a webcam is capable of as well. Can't wait to try this again with the 8" Newt. North is down in this image.