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    Re: HO 211 vs. Bayless
    From: Tony S
    Date: 1999 Jul 04, 6:07 PM

    Paul Hirose wrote:
    > Joe Shields mentioned the version of HO 211 by Bayless.  I bought that
    > book, but still prefer the table in Bowditch Vol 2 (which I assume is
    > identical to the original HO 211), at least at a desk at home.
    While admiring the comparisons you've made, I am obliged to point out that
    work included two methods: AP and DR sources. Exactly where the "HO 211" came
    I'm uncertain. But it is the most quoted and tabled in Bowditch.
    My Ageton source is his preface note dated Jan, 1961 in:
            Manual of Celestial Navigation
            Copyright 1942, 1961 by
            D. Van Nostrend Company, Inc
            First Published, April, 1942
            Nine Reprintings
            Second Edition, January, 1961
    What is very interesting is that there are two distinct tables (AP and DR)
    also take into account base data from The Air Almanac, and includes extensive
    examples of each. His DR method is named Table II in the book ...and it does
    leading duplicate data similar to what Bayless did. The Bayless method does
    to require fewer page openings but, as you point out, the fold back can pose
    other difficulties.
    I found this gem in a used bookstore around 1978 or so. You may be able to
    one too. It's hard back. dark blue/black color, about 108 pp
    > The main advantage is the consistent arrangement of the A and B
    > columns.  HO 211 always puts B in the right-hand column.  Also, the
    > numbers in the B column are boldface, at least in the Bowditch
    > reprint.  Bayless is less Murphy-resistant.  B can be in either
    > column; you have to look at the heading.  It's clearly marked, but you
    > do need to keep your wits about you, more so than with Ageton.
    > HO 211 is able to keep the A and B columns always in the same places
    > because it goes out to 90 degrees on the top column headings before
    > "turning around".  However, the behavior of trig functions is such
    > that the first and second halves of the table are mirror images.
    > E.g., A of 10 deg = B of 80 deg.  Bayless takes advantage of this by
    > only going to 45 degrees before turning around.  It cuts half the size
    > off the table, but also forces A and B columns to swap places.
    > I'm sure Ageton was aware of the redundancy in his table, but accepted
    > it in the interest of reliability.  After all, it only costs 18 more
    > pages.
    > Another complaint is that Bayless likes to omit leading digits, if
    > they're identical for several entries in a row:
    >  Ageton     Bayless
    >  163322     163322
    >  162738       2738
    >  162250       2250
    > Perhaps I just have a mental block, but the Bayless format is
    > slower for me to absorb.
    > One practical matter is that Bowditch vol. 2 is a large book and lies
    > open to any page in the table.  Bayless is a small paperback and tends
    > to flip closed if you let go of it.  (However, a 1940s-vintage HO 211
    > for air navigation owned by a friend has the same problem.)
    > For negative altitudes, the rules in Bayless are incorrect.
    > I must say there are some good points to Bayless.  Tabulating only
    > whole minutes simplifies the Bayless table.  Each column contains
    > one complete degree.  On the other hand, Ageton only covers a half
    > degree per column, since 120 entries won't fit.  If you want to
    > look up, say, 16 deg 48 min, find the 18' row in the 16 deg 30'
    > column.  Not hard, but I've managed to botch it.
    > The Bayless table has a clean, uncluttered look compared with the many
    > unneccessary dividing lines in Bowditch.
    > Neither table does a good job indicating the left-hand minutes column
    > goes with the top column headings and vice versa on the bottom,
    > though.
    > Bayless does include a method, devised by guru D.H. Sadler (of the
    > Royal Observatory, I believe) for solving sights when LHA is near 90
    > or 270.  HO 211 becomes very inaccurate in such circumstances.
    > The Bayless table only has 1/4 the number of pages as HO 211.
    > Mike Pepperday's S-Table is yet another Ageton variant.  Like Bayless,
    > he eliminates redundancy by turning the table around at 45 degrees.
    > His main improvement is to number the table all the way to 360
    > degrees.  You can enter his table with LHA directly, instead of having
    > to convert to meridian angle if LHA is more than 180.  Additional
    > hand-written column headings would let you do this with the other HO
    > 211 variants, of course.

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