SaratogaSkies Jim Solomon's Astropics


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Outer Planets (Jupiter Uranus Neptune)

Image Details:

Camera: SBIG ST-2000XM
Mount: Astro-Physics 1200GTO
Scope: AP Starfire 160EDF APO Refractor
Configuration: Negative Projection (Barlowed)
Additional Optics: TeleVue 5x PowerMate
Filter: Astrodon RGB I-Series Filters
Effective Focal Length: 6185mm
Effective Focal Ratio: f/38.7
Exposure: Jupiter: 50 × 0.1s; Uranus & Neptune: 100 × 1s {R,G,B}
Total Exposure: 0hrs, 3min
Date: 8/26/2008 9:45 PM PDT
Location: Saratoga, CA, USA
Acquisition: CCDSoft
Focus: FocusMax
Dithering: None
Guiding: None


  • IRIS: Registration, Wavelets, White balance, G2V calibration
  • JimP: Dark subtraction, Flat field, Kappa-Sigma Stacking
  • Photoshop: Compositing, JPG conversion

Image Description:

This is my first attempt at imaging planets with an astronomical CCD camera, as opposed to with a webcam or DSLR. Uranus and Neptune are particularly difficult targets, given their tiny apparent sizes (3.7” and 2.3”, respectively). I did a G2V star color calibration, corrected for atmospheric extinction, in order to get as accurate a color balance on Uranus and Neptune as possible. On a decent monitor, the difference in color between those two should be fairly obvious. All in all, given the wrong tool for the job — a CCD with a painfully slow frame rate — and the awful seeing, I'm pretty pleased with the results. Jupiter was done as a “control” group to make sure I didn't get carried away with wavelet processing. In fact, I used the same wavelet coefficients on all of the individual images. The image is a composite pasted together in Photoshop of the highly cropped, but nonetheless full resolution images. Hover the mouse over the image to see the labels, although such should not be necessary given the highly educated nature of the visitors to my web site! <smile> North is up.