Talk:Solar eclipse of April 29, 2014

zero second eclipse?

In case anyone is interested this solar eclipse seems to be unusual in that the sun is not completely above the horizon when "annularity" occurs which would seem to make the fact that it is a central eclipse irrelevant as nowhere on earth will you be able to actually see it unobscured by the earth itself. There is no time or path width listed in the master canon at NASA. TimL • talk 15:13, 5 November 2013 (UTC)[reply]

It is unusual, but maybe not quite as you describe, but it does look like an extreme limit. The center of annularity misses the earth ( That's what the -1.00001 gamma means), while somewhere in Antarctica there will be an annular eclipse which is a tangent contact, but if you were "taller" by some number of meters or kilometers, you'd see a nonzero duration. Perhaps someone will do some more detailed calculations before then, showing antarctic geography elevation and where the view is optimal. Tom Ruen (talk) 22:38, 5 November 2013 (UTC)[reply]

I added a simulated view from 70S, 131E, 0 meter elevation, near the greatest eclipse, a nice annular view, but you need a very accurate simulation to know exactly what's happening. Tom Ruen (talk) 02:13, 6 November 2013 (UTC)[reply]

Looking again at the NASA graphic, my GUESS is that the duration is NOT ZERO, but really was "not computed" because the center of the shadow missed the earth. Tom Ruen (talk) 02:17, 6 November 2013 (UTC)[reply]

Thanks. Very interesting. Does your simulation account for atmospheric refraction near the horizon, in this "extreme limit", as you say, that could make quite a difference. Wonder if anyone will make the trip to see it to know for sure. ;-) TimL • talk 23:03, 6 November 2013 (UTC)[reply]

No atmospheric refraction for my program, but that mainly allows you to see slightly below the horizon. My main worry on accuracy is timing, since perturbations generally cause events to oscillate early or late. My calculations are from Jean Meeus [http://www.amazon.com/Astronomical-Formulae-Calculators-Jean-Meeus/dp/0943396220], with 6 pages of trigonmetric variation terms, its crazy anyone would use a calculator, and still it can be possibly off by minutes in timing. Tom Ruen (talk) 00:33, 7 November 2013 (UTC)[reply]

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