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.

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.