NavList:

John,

A set of four consecutive almanacs works fine for Sun and Aries. Moon,planets, and polaris tables require a current almanac. I use Kolbe's almanac to update Aries GHA, Sun GHA and declination. On the 2008 Nautical Almanac for today 24 December 2012 the Sun GHA correction is -0.07' Declination correction -0.07'. The corrections are small enough to ignore. Aries GHA 2008 almanac correction is +1.84' and should be applied.

Greg Rudzinski

[NavList] Re: Martelli's Time-Sight Tables
From: John Brown
Date: 24 Dec 2012 10:15
Merry Christmas to you Hewitt, and to all Navlisters.

Reeds Astro Nav Tables are also available from Amazon for earlier years.

I believe it is possible to part exchange old for new with Amazon, and I have been wondering what the market is like for old almanacs? - probably better than for old tide tables, anyway. :-) It occurs to me that having Reeds for four consecutive years would serve as a ready source of the ephemeris with (or without?) the quadrennial corrections. In any one year, three of them could be left on the bookshelf and one taken to sea. Four almanacs, with their sight reduction tables, are together a lot slimmer than Nories, but in A4 format.

Can anyone shed light on the accuracy of using an almanac that is exactly four years out of date? I know this is the basis for many long term Almanacs - HO 249, Bowditch, Geoffrey Kolbe etc.

John
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