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Dear Bruce,
Thank you very much for your offer
(my mailing address and my fax number are in
an off-the-list message).

In veiw of our recent discussion under the title
"Frank's formula" I am afraid that the occultation method
will give poor results without a sextant.

The moment of occultation will be hopelessly spoiled
by the Moon parallax, and to take this parallax into account
we will need the Moon's altitude at the moment of occultation,
And, unfortunately, this is exactly the case when we will
need it with high precision:-(

Alex.


On Tue, 2 Nov 2004, Bruce Stark wrote:

> Alex,
>
> Raper's "Practice of Navigation" has three pages on Finding the Longitude by
> Occultation. Here are two passages, one near the beginning, the other at the
> end:
>
> "This observation affords, in favorable cases, the most decisive results,
> because it is both instantaneous and altogether independent of instrumental
> adjustments."
>
> "The case least liable to error on the several accounts enumerated are those
> which occur when the moon is near the meridian, and in which the central zone
> of the moon passes over the star. The emersion from the dark limb is the case
> most distinctly marked."
>
> If you like, I'll send you photocopies of the three pages. But you'll have to
> send your US mail address soon, as Janice and I are leaving again shortly,
> and will be gone for several weeks.
>
> Bruce
>
>

   

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