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Ursa Major Rising - Anza Borrego




Scope: EF18-55 DSLR Lens at 18 mm, f/4.5; Location: Blair Valley, Anza Borrego Desert, CA;  27 December, 2008; Camera: Canon XT 350D (Baader ACF modified)

Exposure: 5 x 8 min   (no filters)  ISO 400, 6 Darks, no Flats 

Processing: Images were captured with DSLR Focus  and saved as RAW file format. Images were decoded and dark corrected in IRIS. Since there is no camera tracking motion, images were arithmetically added in IRIS. Dark point equalization and rough color balance  were done in IRIS.  Image was saved as Tiff.  Star trails are sequenced in 8 minute steps. Land features and sky background are additive creating the perception of a bright sky and landscape. The sky was darkened somewhat and the landscape lightened.  A color adjustment was done for low signal intensity level by lightening the blue channel. Final stretching and touch up was done in PhotoShop.  Final Image size is approximately 3474 x 2314, but the highest resolution on the web page is 2100 x 1400.

This image is taken from Blair valley with camera pointed Northeast to capture Ursa Major rising. The two bright streaks toward the center of the image are the North Star pointer stars  (Dubhe and Merak). The stars are wheeling about the Earth's northern axis of rotation.. The exposure time of the multiple images shows the stars trailing around the Earth's axis of rotation .  The lighter sky near the horizon is due to a light haze in the area catching some of the light from a small community toward the North.  Horizontal FOV is 65 degrees

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All images and content remain the property of Jim Thommes - copyright 2003 - 2012

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