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    Long Term vs Annual Almanac
    From: Geoffrey Kolbe
    Date: 2015 Dec 1, 13:20 +0000


    On Nov 30, 2015, at 8:35 AM, Mark Coady <NoReply_MarkCoady@fer3.com> wrote:

    It has been a December tradition for me to pick up the Nautical Almanac for the next year (and Eldridges for tides,  Merry xmas to me,LOL).  I Prefer the hardcover for nostalgic reasons of real books, but usually pick up the Blue Softcover Commercial edition, readily available at local haunts like West Marine, Landfall, and Defender.

    I noticed prowling Amazon the other day there is a long term Alamanac, hypothetically good till 2050.  Which exceeds my probable life span.

    I assume that it is an Almanac with corrections, such as we might do if faced with using an expired almanac a year or two old in an emergency.

    Am i right?, does this add a step and yet a new place for possible distracted error? is it worth my while?  I am kind of fond of the tradition of my New Almanac each year for reasons of emotion not logic. 


    ​With celestial navigation no longer the main means by which we keep ourselves found, it is easy to forget the annual tradition of acquiring a new Nautical Almanac, so it makes sense to have an almanac that will be 'in date' to hand whatever the circumstances. There is no reason why you should not buy a Long Term Almanac and carry on with your traditional purchase of an NA, of course :-) ​It does not have to be a choice of one or the other - buy both! The LTA will last a lifetime and it can be bought as a hardback book.

    Given the abbreviated nature of the LTA, here will naturally be a few extra steps to generating the GHA and Dec of the sun/star for any given time. But I hope I have made the process as easy as possible so that the extra work involved is not burdensome - especially if you get used to using it.

    Accuracy should be good to around 0.3 MOA for the whole 50 years of the validity of the almanac. This is not as good as the NA, but it is actually small enough that it will not significantly add to the error of working up a position line.

    Geoffrey Kolbe
       
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