Surely the proximity of the Moon to the surface of the Earth
makes the timing of an occultation dependent on where you are on the
Earth's surface. (Parallax error)
The calculations to correct for this must make it a mathematicians
picnic.
Nevil Maskelyne, tormentor of John Harrison, advocated "lunar
distances" but it was not practical,
as is demonstrated by it never being used.
Telling the time on the Earth's surface was commonly done with a sun
dial, and these can be refined to a fraction
of a minute. With about 30 years of observations this should be able
to discipline an atomic clock to a second or better,
and reach the limit of stability of the atomic clock.
cheers, Neville Michie
On 29/01/2012, at 3:46 AM, [email protected] wrote:
The star catalog specifically designed for lunar occultations is
the XZ (I'm guessing it stands for eXtended Zodiacal) Catalog from
the US Naval Observatory. It's based on the earlier ZC and covers
the band of brighter stars that can be occulted by the moon. Simbad
should have these catalogs.
Aart Olsen
----- Original Message -----
From: "Chris Albertson" <[email protected]>
To: [email protected], "Discussion of precise time and frequency
measurement" <[email protected]>
Sent: Thursday, January 26, 2012 10:42:00 PM
Subject: Re: [time-nuts] telling time without a clock
"simbad" is a catalog of catalogs with a built in web based search
engine. It is pretty much what "everyone" uses to search. You can
define a shape and ask for all objects that meet some criteria that
are within that shape. Other software can plot the result for you as
a chart If it is not in Simbad you have likely discovered something
new.
http://simbad.u-strasbg.fr/simbad/
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