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Gordon Talge wrote-

>Will all this stuff about "Errors" in Cotter's book,
>somebody must not have proofread it.

Well, a proofreader usually knows little about the topic of a book, so can
only spot divergences between the author's text and the printed copy. Only
a few of the errors Jan and I have uncovered came into that category. Most
will have been in the original text.

>Don't they usually submit a book to a committee for
>peer review, and then to an editor for proofreading

Peer review would often (but not always) happen in a scientific journal,
but I suspect it is rare in book publishing.

Nautical books were something of a speciality of the publishers, Hollis &
Carter, and their nautical books had a General Editor, Mike Richey. Mike
was at the time, and for many years after, Secretary of the Institute
(later the Royal Institute) of Navigation, and co-authored "The Geometrical
Seaman" with Prof. Eve Taylor. He has become known for his slow
single-handed passages in transatlantic races in his junk-rig Folkboat,
"Jester". So there should have been expertise available to make a careful
check of Cotter's book. It's a pity it didn't happen.

>BTW, I recently bought a used book called, "self-contained
>Celestial Navigation with H.O. 208", by John S. Letcher, Jr.
>Copyright 1977 by International Publishing Co.

I have a copy of this book, which I rather like. His "long-term almanacs",
in the appendix, expired in 2001, unfortunately. Letcher also wrote a
useful book about self-steering. His long distance ocean sailing in those
days was done in very small craft, 20 ft, and later 25 ft: quite an
achievement.

I referred to "Letcher's Method", for clearing the lunar distance, in my
musings  "About Lunars". It seems to work well enough for the purposes of
small-boat sailors.

>It is full of errors also. Fortunately, the previous owner
>was meticulous and neat corrector.

I wasn't aware of these errors, but would like to be. Would Gordon kindly
provide, for list-members, page-references to passages he (or the previous
owner of the book) is suspicious about?

>Anyway, Letcher has a chapter on a method called "Time by
>Lunar Lines of Position". On the cover it says that
>"With no time signals and an untrustworthy timepiece,
>he found his longitude by discovering a modern solution
>to the method of lunar distance that served Slocum so well."

This method is alright in principle, but has a flaw in practice, which
Letcher (to be fair) acknowledges. Measuring altitudes up from the horizon
introduces serious errors (because of uncertainties in the direction of the
horizon) which the lunar distance method avoids. Obtaining time from the
Moon imposes such demands on accuracy that only the lunar distance method
is really viable. That's my opinion, anyway. This question has come up on
Nav-L before, and no-doubt will again. If anyone asks, I will try to dig
out the old correspondence. The matter was thrashed out years ago in the
Journal of Navigation.

>The guy has a Ph.D. in aeronautics and applied math from Caltech,
>so I have no dout he knows what he is talking about.

I agree that he does, whether or not the Ph D is responsible for it.

>Wonder if anyone else on the list has heard or used this method.

I also would be interested to know if anyone else has ever tried such a
method, of lunars-by-altitude, rather than lunars by lunar distance. It was
proposed by Francis Chichester, among others.

George Huxtable.



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