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I agree with the conclusion, given the premise.  The premise has not
been established with certainty however.

Fred

On Dec 23, 2003, at 10:47 AM, Steven Wepster wrote:

> Hi all,
>
> Concerning the errors that Slocum would have discovered, let me add
> this.
>
> An article appeared in the 'Navigation'  journal (Vol. 44 no. 1, 1997)
> in which the author (S.Y. van der Werff) discusses lunar distances and
> particularly the lunar distance observation of Joshua Slocum on june
> 16, 1896, shortly before his landfall on Nukahiva. He comes up with a
> completely different kind of error that Slocum discovered and
> corrected.
>
> Van der Werff notes that the Nautical Alamanc uses the astronomical
> date convention, i.e., a new day begins at noon, not at midnight. The
> layout of the lunar distance tables is such that one can not be
> mistaken by 12 hours, but not so the right ascension and declination
> tables. Van der Werff's suggestion is that Slocum accidentally took
> the RA/Dec values for a time 12 hours off (12 h too late, actually).
> Slocum's 'discovery', then, was that the tables were 12 hours off.
>
> If that was indeed the error that Slocum made, I conclude that he was
> _very_ unfamiliar with the time convention in the almanac. He would
> have had no earlier occasion to stumble over this difference of 12
> hours, or at least no such occasion had occured in the voyage with
> 'Spray' and for quite some time before. It would imply that usually he
> took from the almanac only data that were forgiving of such an error:
> declinations, but no right ascensions. I would conclude that, on the
> large, Slocum's only means of astronomical navigation was by meridian
> altitudes.
>
> Does this appear as a likely scenario to list members?
>

   

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