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Alex Eremenko wrote:

>I am using the "Complete on board Celestial Navigator" which lists
>the Sun position with only 1' precision. I hope that more precise
>Almanach data will permit me to explore the ultimate sextant
>precision."

and Frank Reed commented-

>By the way, I think the "Complete On-board Celestial Navigator" is very
>clever, and its accuracy is sufficient for the realities of standard late 20th
>century position line navigation.

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Users of Bennett's "The Complete On-Board Celestial Navigator" need to be
aware that under certain circumstances, for bodies which are roughly East
or West of the observer, the Azimuth table can give results that are very
significantly in error, with errors many times greater than the "one or two
degrees" quoted by the author; a defect that he has acknowledged.

There has been much previous discussion on this matter on the Nav-L list,
some of it highly acrimonious, which I don't intend to stir up again. But
newer joiners to our list may be unaware of certain criticisms of Bennett's
tables, which in other respects may indeed be admirable.

However, I refer those interested to postings in Nav-L archives around 3
March 2003 and subsequently, under threadnames such as "The Complete
On-Board Celestial Navigator Second Edition", and perhaps also in early
September 2003, under "Principles and being practical".

And I recommend that navigators use some other method than Bennett's
Azimuth Tables (for example his Weir diagram) for azimuths that are within
15 or 20 degrees of due East or West.

George

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contact George Huxtable by email at george@huxtable.u-net.com, by phone at
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