SaratogaSkies Jim Solomon's Astropics


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!


M4 & IC 4604 (Antares / ρ Ophiuchi / M4)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
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: 16 x 2min @ ISO 400
Total Exposure: 0hrs, 32min
Date: 5/11/2005 1:31:15 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


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

Image Description:

This is my second "test photo" with my new Canon EF 200mm f/2.8L II USM lens. This is a spectacular field at the border of the constellations of Scorpius and Ophiuchus; one that I need to revisit when it's better placed. (It was low to the horizon, in a light-polluted portion of the sky, at the time this was shot.) This image also could use much more exposure time.

Here are the highlights of this colorful region of the Milky Way:

  • Starting in the lower right-hand corner is the red-giant star Antares, the brightest star in Scorpius. The yellow reflection nebula surrounding Antares is IC 4606, and the small globular cluster within that nebula (toward the center of the frame from Antares) is NGC 6144.
  • Directly above Antares is the large, globular cluster, M4.
  • Above and to the left of M4 is another bright star, σ Scorpii. Surrounding σ Scorpii is the blue reflection nebula Ced 130 and red emission nebula Sh 2-9.
  • Continuing counter-clockwise, on the middle-left side of the frame, is the triple star ρ Ophiuchi. Surrounding ρ Ophiuchi is the blue reflection nebula IC 4604. To its right is the blue reflection nebula IC 4603.
  • Below and to the right of IC 4603 is 22 Scorpii and the blue reflection nebula IC 4605.
  • Finally, the dark regions throughout the left half of the image are various and sundry dark nebulae; i.e., clouds of dust which block our view of the stars and other objects behind them.

North is to the right in this image.