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    Re: Azimuth Formula Questions
    From: Doug Royer
    Date: 2005 Nov 1, 10:00 -0800

    Bill wrote:
    
    Thanks to you and many others on the list, I have exceeded my initial goal
    of 229 reductions, and can now knock off a reduction on a $10, 3-memory
    TI-30XA  using only the daily pages in less than two minutes.  But still so
    much more to learn.
    
    Hope you will give 229 a look.  Not ideal in strange circumstances, but does
    work well for recommended observations.  Coupled with an almanac, no
    electricity, calculators or computers required (other than generating the
    volumes ;-)  Pencil and paper only.  A great backup to GPS backup. 
    
    It also has other tricks to play with the tables, such as star location or
    identification, great-circle route calculation, and a table of offsets to
    correct the LOP from a long intercept to more closely approximate a COP.
    Not as painless as a calculator, but not rocket science either.  Heck, even
    I can do it!
    
    Bill
    
    "Hope you give 229 a look".
    
    Yes, it's a great tabular method. It also has the ability to to perform
    other functions as noted.
    When I started out I was taught reduction using HO-208. HO-208 is a little
    more tedious to use than is HO-229 but gives real solid results. HO-208 also
    
    is able to perform the same other functions as HO-229.
    Because of the number of volumes needed to cover all latitudes by both
    HO-208 and HO-229 methods we started using HO-249 vol. I for everyday use.
    This is quick and easy to use to reduce data but has drawbacks and only
    covers those latitudes used most. Nutation and only 5 stars to chose from
    with the 3 best stars noted for a particular LHA. But you can get by
    nicely,for the most part,with just 1 volume aboard the vessel. Volumes II
    and III cover everything else and have much greater flexibility(as they are
    built to use with the same format as HO-229). But,again,one now has multiple
    volumes to lug around to be able to cover everything.
    I learned and then started to use HO-211 on a regular basis. 28 pages of
    data covers just about everything to reduce sights. But that is all it is
    capable of doing. It can't compute GC sailings etc. But being able to reduce
    98% of all sights anywhere with a 28 page book(including procedures to use
    the tables and a work sheet form for reduction using the Ageton Method)this
    is a great tool to have and know how to use.
    There is now a 9 page HO-229(Ageton)reduction book but I have never tried
    it. In older navigation books they usually include the HO-211 reduction
    tables in the rear of the book.
    In the rear of each year's paper NA there is an interesting method with
    tabular reduction tables included. Usually located behind the Polaris tables
    and before the conversion of arc to time tables. I'm describing the
    reduction tables inside the yearly hardback NA. I'm not sure if the
    commercial volume of the NA has these included.
    
    
    

       
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