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    Re: HO 211 Umland version
    From: Paul Hirose
    Date: 2002 Jan 25, 2:15 PM

    I finally took a good look at the version of the HO 211 sight
    reduction table that Chuck Griffiths pointed out for us. Its creator,
    Henning Umland, has made the table available for download on the Web.
    Some of his table's features are arguable. In my opinion there are an
    excessive number of significant digits. For example, in the A column,
    from zero to 50 degrees, there's at least one more significant digit
    than needed for interpolation to .1 minute.
    At 77 45 the A values change from integers to numbers with one decimal
    place. However, they could remain integers all the way up to 85
    degrees and still allow reading to .1 minute.
    I was pleased that this table always keeps the A and B columns in the
    same places, just as Ageton did. Umland also gives you all the digits
    for each table entry. By contrast, the Bayless tables switch A and B
    to save space, and omit digits if several entries in succession begin
    with the same digits. The first trick cuts the table size in half
    without loss of resolution, but I've never understood the missing
    digits thing. Both these "features" demand more presence of mind from
    the navigator than classic Ageton does.
    One good trick Umland missed was the boldfacing on column B that
    Ageton used. It helps the eye without making the table any bigger.
    Showing the integral minute values in red works as long as you've got
    color. But what if the tables are reproduced in black and white? I
    would have bracketed these entries with heavy horizontal lines top and
    bottom. Also, I'd have eliminated the vertical line separating A and B
    for the same angle.
    It's strange that each and every page has the formulas for A and B.
    By the way, Umland's not the first to publish the Ageton method
    tabulated to .2 minute. In Bowditch it says a math professor named
    Hickerson published such a table in 1944. However, his table was
    folded at 45 degrees, so his A and B columns periodically switch
    One of my buddies has a genuine HO 211. It's little. You can hold it
    in one hand while filling out your form. Bayless is small too. The
    main thing I dislike about HO 229 is that the books are so darn big.
    And EXPENSIVE -- the price has jumped way up. But for me 229 is
    quicker than 211 and there's less chance of a goof. I still like HO
    211 though. Did the last Silicon Sea leg that way.
    paulhirose@earthlink.net (Paul Hirose)

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