SaratogaSkies Jim Solomon's Astropics

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NGC 7129 (Reflection Nebula)

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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: 30 x 4min @ ISO 800
Total Exposure: 2hrs, 0min
Date: 10/3/2005 10:12:08 PM 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

Processing:

  • 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 an interesting field in the constellation of Cepheus. In the upper right are a handful of reflection nebulae: NGC 7129, NGC 7133, and IC 5133. In the lower left is the open cluster NGC 7142. This needed more exposure time to bring out the faint portions of the reflection nebulae. A higher-resolution image is also available. North is up.

 
M57 (The Ring Nebula in Lyra)
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:

M57 (The Ring Nebula in Lyra)

Image Details:

Camera: Mofidied Canon Digital Rebel (300D): Hutech (no filter)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Negative Projection (Barlowed)
Additional Optics: TeleVue 2x Barlow
Filter: None
Effective Focal Length: 2250mm
Effective Focal Ratio: f/11.1
Exposure: 30 x 1min @ ISO 1600
Total Exposure: 0hrs, 30min
Date: 6/5/2005 12:40:39 AM 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

Processing:

  • IRIS: Dark subtraction, Flat field, Best frame selection, Registration, Gradient removal, Richardson-Lucy deconvolution, LRGB computation
  • JimP: RGB to Luminance conversion (NTSC weighting), Kappa-Sigma stacking, White balance, ASINH stretching
  • Photoshop: Levels, cropping, JPG conversion
  • Neat Image: noise reduction

Image Description:

This is the Ring Nebula, aka M57, a spectacular planetary nebula in the constellation of Lyra. I'm very proud of this image, as it was taken with a long focal length (2250mm) on a very windy night with horrid seeing. Don't believe me? — then check out this, that, and the other threads on the TAC mailing list describing the conditions in and around the Bay Area on the night of Saturday, 6/4/2005. Told ya!

I'm becoming convinced that the best way to image DSOs at long focal lengths — especially with modest equipment in lousy seeing — is to take a page out of the webcam approach to imaging planets. Namely, take a bunch of short exposures, toss out the bad ones, and stack the remaining ones. That's what I did here, selecting the best half of the 60 frames, and then applying a liberal dose of Richardson-Lucy deconvolution to the luminance channel.

For this image, I used fellow Saratogan Rich S.'s modified 300D, which I think helped to capture a bit more of the red in the outer reaches of the nebula. (Thanks Rich!) Check out my previous attempt at M57 for a comparison. This is the full-resolution image, cropped for display on the web. North is up.