NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2011 Sep 29, 09:35 -0700
Alan,
Explore some of the previous threads on camera CN here:
http://www.google.com/search?hl=en&sitesearch=fer3.com&q=DSLR+camera+celestial+navigation+NavList&btnG=Search&oq=DSLR+camera+celestial+navigation+NavList&aq=f&aqi=&aql=1&gs_sm=s&gs_upl=11813l25006l0l28774l3l3l0l0l0l0l1195l1668l2-2.7-1l3l0
Getting Hs out of a camera requires taking a set of UT timed images (at least 20) through the field of view of a prime fixed focal length lens. From a known position each image needs to have sight reduction performed to a zero intercept. Formula,graphs, and tables can then be made to be kept with the lens so that an Hs can be derived from any pixel height above the horizon using a minutes of arc per pixel value multiplied by the pixel height of the body above the horizon. I find the graph convenient to use on my lap top.
Greg Rudzinski
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