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From: colonel@gloria.UUCP
Newsgroups: net.astro,net.physics
Subject: Re: sunrise and sunset
Message-ID: <739@gloria.UUCP>
Date: Sun, 23-Dec-84 14:24:21 EST
Article-I.D.: gloria.739
Posted: Sun Dec 23 14:24:21 1984
Date-Received: Thu, 27-Dec-84 03:26:23 EST
References: <1043@aecom.UUCP>
Organization: SUNY-Buffalo Confuser Science
Lines: 28

> Does anyone out there know an equation for sunrise and sunset
> given the day of the year?

This isn't quite what you want, but you're welcome to it.  It gives the
DIRECTION of sunset at the solstice at various latitudes.  (One look
will tell you why I wrote it in FORTRAN.)  23.5 is the earth's tilt,
more or less.

	t=sind(23.5)
	print 1, (i, asind(t/cosd(float(i))),i=0,66)
1	format (1x,i2,3x,f8.1)
	stop
	end
	function sind(x)
	sind=sin(x*3.14159/180)
	return
	end
	function cosd(x)
	cosd=cos(x*3.14159/180)
	return
	end
	function asind(x)
	asind=180/3.14159*asin(x)
	return
	end
-- 
Col. G. L. Sicherman
...seismo!rochester!rocksanne!rocksvax!sunybcs!gloria!colonel