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FW: Re: Global oceanic tides,
From: Bill Noyce
Date: 2003 Aug 26, 10:09 -0400
From: Bill Noyce
Date: 2003 Aug 26, 10:09 -0400
Sure enough, this went just to Geoff. I hereby send it to
the list, even though Geoff has already posted the whole
thing...
-- Bill
-----Original Message-----
From: Noyce, Bill
Sent: Monday, August 25, 2003 10:45 AM
To: 'geoff@BUTT.DEMON.CO.UK'
Subject: RE: Re: Global oceanic tides,
Geoff Butt has been calculating NA data, and writes:
> There are however some minor discrepancies
> of the magnitude of 0.2seconds in GHA for some bodies which I don't quite
> understand at the moment
I wonder if this is because the published NA adjusts the apparent
position of planets for the "center of illumination", rather than
the center of mass. For example, when Venus shows a crescent,
the NA will tabulate the planet's position as being somewhat closer
to the sun than it actually is.
-- Bill
