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Posting-Version: version B 2.10.2 9/18/84; site watrose.UUCP
Path: utzoo!watmath!watrose!gwhawkins
From: gwhawkins@watrose.UUCP (gwhawkins)
Newsgroups: net.astro
Subject: Re: StarDate: March 28 Goodbye Venus
Message-ID: <7425@watrose.UUCP>
Date: Sat, 6-Apr-85 16:43:24 EST
Article-I.D.: watrose.7425
Posted: Sat Apr  6 16:43:24 1985
Date-Received: Sun, 7-Apr-85 04:13:57 EST
References: <6@utastro.UUCP> <181@tektools.UUCP> <580@lsuc.UUCP>
Organization: U of Waterloo, Ontario
Lines: 21

> > What is the highest Venus ever gets?
> Simplifying the
> orbits to coplanar circles, this occurs when the Earth-Venus-Sun angle is
> 90 degrees.  (Oddly enough, this situation was also described in net.puzzle
> a couple of months ago -- with respect to clock hands instead of planets!)
> Mark Brader
 
Before you go and brush up on your spherical geometry (I boo-booed and deleted
his comment on that) you should brush up on your planar geometry.  Your 
statement about highest angle above the horizon at 90 degrees is a gross
oversimplification.  All you have to do to show this is draw the orbit of
Venus on paper (admittedly a big sheet of paper); pick a position for the
earth; and draw the hypotenuse of your 90 degree triangle.

You'll find that the hyp. passes inside the orbit of Venus.  Using
circular co-planar orbits and no atmosphere, etc., the maximum angle
above the horizon is found by drawing a line from the earth TANGENTIAL
to the orbit of Venus (again, a very long line).

		larry fast (Universty of Waterloo)
		broadcasting from exile