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Subject: Re: On the Mischief of Geographical Position.
daveweilacher@XXX.XXX
Date: Thu Jan 24 2002 - 15:10:05 EST
..It is the ZENITH distance... Dave Weilacher did not write this. Hebert Prinz did.
I am too much of a simple minded, sometimes single handed, sailor, to put that much thought into it.
I was arguing against the validity of it, is all.
Dave Weilacher
Original Message:
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From: Michael Wescott wescott_mike@XXX.XXX
Date: Thu, 24 Jan 2002 14:49:20 -0500
To: NAVIGATION-L@XXX.XXX
Subject: Re: [NAV-L] On the Mischief of Geographical Position.
daveweilacher@XXX.XXX wrote:
>> It is the
>> ZENITH that the navigator is attempting to locate in the celestial
>> sphere. Once that has been accomplished, he projects it down via the
>> local vertical, simply by renaming declination latitude, and GHA
>> longitude, and calls it his position . This works on an egg, a pear, a
>> lemon or an onion.
Rodney Myrvaagnes <rodneym@XXX.XXX> replies:
> This is rigorously true, but it dodges the question that I think
> people meant to ask, vis: If the local vertical (gravitationally
> determined) doesn't point to the center of the earth or the celestial
> sphere, then where is the position so measured?
The actual (meaning the astronomical) latitude and longitude of a
place is what is measured. In other words, the position so measured
is exactly that place where it is measured. Due to local gravitational
anomalies there may even be other places nearby with the same
astronomical latitude and longitude.
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