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Steven Wepster wrote:

> Good luck indeed! But after 2100 feb 28, you (or, more likely, a
> future generation) could still use them provided that you subtract one
> full day from the date.
>

Steve and all,

That's true, but "Bowditch" doesn't tell us so.

This simple fix equally applies to the declination tables for the years
1791 to 1806 in J.H. Moore's _ New Practical Navigator_, of which the
American version was a plagiarism. The correction of some "8000 errors" in
this book has always been played up as it was the main excuse for the
appropriation of the text and its subsequent re-edition under a new name.
Is it not highly ironic then that, after repeating for nearly two
centuries in the foreword of every single "Bowditch" edition the story of
how Moore's table for 1800 was wrong by as much as 22' of arc, the modern
editors would finally commit the exact same mistake?

The mistake, by the way, is not in the tables; they could not be
constructed in any other way. The mistake is in the instruction how to use
them (either by specifying Steve's rule, or by limiting the range of
validity).

Those who want to use Moore's tables in historical work or such should be
aware that the description itself of the error in the foreword of
"Bowditch" is inaccurate. A casual reader might be mislead into thinking
that only the declinations for the year 1800 are wrong. In fact, the
tables are wrong for all subsequent years, too.

Herbert Prinz

   

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