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...I like Norie's compact size (Burton's is even smaller but its tables carry
less precision, giving answers more like those of Pub 249) and if room
allows, I will carry Pub 249 vol 1, 2, and 3 for plannig sights and quick
work and also carry Norie's for sight reduction or sailings problems not
covered by the declination range or stars listed in 249. Plus it's just fun
to do a sight reduction using the cosine-haversine method!

Norie's gives the observation "How far a Navigator is justified in working
to tenths of a minute is a matter that can be argued about indefinitely, but
since the nautical almanac gives hour angles and declinations to tenths of a
minute and modern sextant with a decimal vernier enables readings to be
taken to tenths of a minute as well, it would seem only logical to use
navigation tables which, with the minimum of effort, provide for the same
order of precision" (Norie's Nautical Tables, Capn. A. G.Blance (ed),
Revised Edition 1991, pp 13-14).

Rod Deyo



As I've mentioned previously, I'm a big fan of Ageton's tables because I'm
enough of a pragmatist to accept that .5' solutions fit well with the accuracy
of my sights. But, I really enjoy the elegance of the cosine-haversine method
enough to wonder why it hasn't found more modern followers.

I see any sight reduction method that works from one's DR position as a big
advantage over AP methods. While I accept that both approaches offer
theoretically equivalent accuracy, I prefer working directly from my DR for the
following reasons:

1. I have a pretty good idea how good my sights and solutions are as soon as I
calculate my intercepts. (Rather than having to complete plotting the LOP's to
know if I'm way off.)
2. I can use high angle sights without having to correct for the curvature of
LOP's. (Something that I see a lot of people neglect, in fact, the table for
this correction isn't even in the 1995 Bowditch.)
3. Any of the sight reductions methods that work from a DR are, I think, easier
to use for Great Circle solutions.

I think the reason HO 229 is so popular is that all those big volumes look so
pretty on one's bookshelf. :-)

Chuck


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