SaratogaSkies Jim Solomon's Astropics


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M86 & M84 (Virgo Galaxy Cluster)

Click to see high-res version.

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: Promaster 72mm UV Filter
Effective Focal Length: 200mm
Effective Focal Ratio: f/2.8
Exposure: 21 x 2min @ ISO 400
Total Exposure: 0hrs, 42min
Date: 5/10/2005 11:01:57 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


  • 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 image is a "do over" of my "first light" image with a new Canon EF 200mm f/2.8L II USM lens. It's 200mm focal length gives a generous 630' x 420' field of view in the Digital Rebel (300D). The crop shown above is a portion of the galaxy-rich region in the constellation of Virgo known as Markarian's chain. This version has much more exposure time than the original and shows more detail with less noise. The upper-left to lower-right smearing is the result of guiding error, differential flexure in the adpater plate, the lens being slightly out of collimation, or a combination of these factors. Need to get to the bottom of this. North is up in the above image. Be sure to check out the entire annotated field from which the above image is cropped. (Note: North is right in the full image.)