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Nautical Almanac usage
I am learning celestial and found in the "abandoned gear" bin at my
club a copy of the 1983 Nautical Almanac, produced by both the UK and US Hydrographical offices (or equivalents). As I read my celestial nav books, this publication is referenced frequently, as are the HO 229 and other sets of government produced tables. My question is this: For the purposes of teaching myself sight reductions, the math aspects and accuracy with a sextant (I have a new Astra IIIB), do I need a *current* Nautical Almanac? It strikes me that if I rule out lunar cycles and the very small changes of the precession of the equinoxes, the data of 22 years ago on the same dates isn't going to be widely variant. Or am I missing something and should I order the 2006 edition immediately so I can do land-based reductions all winter and be competant for the spring? R. |
#2
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Depends on what you want to do. If you want to learn all about serious
celestial navigation, then get up to date almanac - and a good text book. If you want to learn use of sextant, and check your sights with actuak position get one of the cpmputer programs that will provide all the nautical almanac stuff (you don't see it being used) and do all the calculations for you. I did a circumnavigation 50 years ago - long before GPS - and did the calculations the hard way. Now have just from San Francisco to Australia, and took along my old sextant for fun, but used my laptop for all the maths. I think there are quite a few such programs. I use one which I got from web site www.tecepe.com.br When I got it, it was free or shareware, but I think there may now be a charge. It is extremely good, and that site has a lot of other good nav stuff. . but if you want to get right down to basics you will need a nautical almanac - there are also sites where you can get nautical almanac data on the net. Have fun. Terry "rhys" wrote in message ... I am learning celestial and found in the "abandoned gear" bin at my club a copy of the 1983 Nautical Almanac, produced by both the UK and US Hydrographical offices (or equivalents). As I read my celestial nav books, this publication is referenced frequently, as are the HO 229 and other sets of government produced tables. My question is this: For the purposes of teaching myself sight reductions, the math aspects and accuracy with a sextant (I have a new Astra IIIB), do I need a *current* Nautical Almanac? It strikes me that if I rule out lunar cycles and the very small changes of the precession of the equinoxes, the data of 22 years ago on the same dates isn't going to be widely variant. Or am I missing something and should I order the 2006 edition immediately so I can do land-based reductions all winter and be competant for the spring? R. |
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