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Re: Slocum's lunars
From: Frank Reed CT
Date: 2003 Dec 23, 18:27 EST
From: Frank Reed CT
Date: 2003 Dec 23, 18:27 EST
Steve Wepster wrote:
"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."
Does anyone have a copy of this that you could e-mail or fax to me? I've seen references to it on the web, but I haven't been able to locate it (online).
And:
"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."
Aha. That's certainly a possibility.
"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?"
It's an interesting speculation. It might explain Slocum's reaction to his "tables", but without further hard evidence I don't think one can go further..
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
"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."
Does anyone have a copy of this that you could e-mail or fax to me? I've seen references to it on the web, but I haven't been able to locate it (online).
And:
"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."
Aha. That's certainly a possibility.
"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?"
It's an interesting speculation. It might explain Slocum's reaction to his "tables", but without further hard evidence I don't think one can go further..
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
