SaratogaSkies Jim Solomon's Astropics

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December: Test shots with new scopes/mounts

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M16/M17/M24 (Widefield)

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Image Details:

Camera: Mofidied Canon Rebel XT (350D): Hutech Type I Filter Replacement
Mount: Celestron AS-GT
Scope: Canon EF 200mm f/2.8L II USM lens
Configuration: Prime Focus
Additional Optics: n/a (Prime)
Filter: None
Effective Focal Length: 200mm
Effective Focal Ratio: f/2.8
Exposure: 8 x 4min @ ISO 200
Total Exposure: 0hrs, 32min
Date: 8/24/2005 9:28:26 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
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Photoshop: Levels, image scale, JPG conversion

Image Description:

This is "Second Light" for my new, modified, Canon EOS Digital Rebel XT (350D). (First Light is available as well.) I was only able to get 8 exposures in before the marine layer (fog) wiped me out, but the modified camera captured a decent amount of Hα from these relatively bright targets in that relatively short window. This is a well-traveled field in Sagittarius containing several of the showcase Messier objects of summer: M16 (the Eagle Nebula), M17 (the Omega Nebula), and M24 (Sagittarius Star cloud), plus some other goodies. This is the full frame, shrunk for display on the web. A full resolution image is also available. North is right.

 
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)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
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: 2844mm
Effective Focal Ratio: f/14.2
Exposure: 13 x 1min @ ISO 3200
Total Exposure: 0hrs, 13min
Date: 6/23/2004, ~3am PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: None

Processing:

  • IRIS: Dark subtraction, flat field, registration, stacking
  • Photoshop: Noise reduction, levels, cropping, JPG conversion

Image Description:

This magnification pushes the limits of my mount, especially without [auto]-guiding. Only 13 of the 32 frames were useable. The rest showed severe smearing/trailing and had to be tossed. This is a crop of the full-size frame. North is up.

In the "trip down memory lane" category, here is an old image I captured back when I first got my scope and borrowed a friend's Nikon D100. This was 20mm eyepiece projection (1910mm, f/9.6), 1 x 2min exposure @ ISO 1600, dark-frame subtracted and processed in Photoshop. I think my technique has come a long way since then!