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From: steve@jplgodo.UUCP (Steve Schlaifer x3171 156/224)
Newsgroups: net.space
Subject: Re: "At the moment Uranus's south pole points..."
Message-ID: <577@jplgodo.UUCP>
Date: Mon, 24-Feb-86 16:22:47 EST
Article-I.D.: jplgodo.577
Posted: Mon Feb 24 16:22:47 1986
Date-Received: Sat, 1-Mar-86 00:43:47 EST
References: <860217-235409-1418@Xerox> <287@drivax.UUCP>
Organization: Jet Propulsion Labs, Pasadena, CA
Lines: 26
Summary: north pole and spin axis

In article <287@drivax.UUCP>, holloway@drivax.UUCP (Bruce Holloway) writes:
> In article <860217-235409-1418@Xerox> Murray.pa@XEROX.COM writes:
> >How do I tell which end is North and which is South? I assume that the
> >"North" pole of Mars is the one that's pointing roughly parallel to the
> >North pole of Earth. That doesn't transfer to Uranus very well.
> 
> I think "North" probably means the pole that, when looking down directly
> above it, the planet seems to be turning counter-clockwise. Is this right?
> 
According to the IAU, the planetographic north pole of a planet is the one
that is above the invariant plane.  This is very close to the ecliptic plane.
For some planets, Venus for example, this means that when you look down on the
north pole, the planet spins clockwise.  For others, Earth for example, the
spin is counter-clockwise.  In this system, Uranus spins clockwise when you
are above the north pole.  Don't flame me over this choice of convention I
don't like it myself.

Opinions expressed are my own and not necessarily JPL or NASA.

-- 

...smeagol\			Steve Schlaifer
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