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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Image of Earth - what is GHA and Dec of the Sun?
From: Ed Popko
Date: 2015 Jul 24, 12:57 -0700
From: Ed Popko
Date: 2015 Jul 24, 12:57 -0700
Attached is an image of Earth taken by NASA's Deep Space Climate Observatory satelite on July 6, 2015 and posted today on CNN's Week in Pictures news (7/24/2015).
What's unusual is the Earth is fully lit. Thus the satelite is very near or on the axis between the centers of the Earth and Sun.
As we look down that axis at Earth we are also looking directly at the Sun's Ground Point. So what is the Sun's GHA and Dec at this photo op moment? The date gives us clue about the Sun's Dec but its GHA needs a little noodling.
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