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    Re: HO229 history
    From: Lu Abel
    Date: 2007 Jan 19, 17:15 -0800

    I'm a bit unconvinced.  My understanding is that HO229 was developed in
    the early days of computers using a computer to calculate the values in
    the tables, with the objective of producing tables that were accurate to
    0.1 minute.   This is supported by the preface material in 229.
    
    Calculating a great circle distance is no different than calculating a
    Hc (use DR for start point, GP of body for end point), except that GCD =
    90 degrees minus Hc.
    
    Your friend's story might have stemmed from another, very true bit of
    early computer history:  The development of the very first electronic
    computer, ENIAC, started during WW II to calculate artillery firing
    tables.  I'm not an artillerist, but I understand that precision aiming
    of long-range artillery includes all sorts of factors, including even
    temperature, humidity, and barometric pressure, so any artillery piece
    requires enormous firing tables.   See
    http://ei.cs.vt.edu/~history/ENIAC.Richey.HTML
    
    Lu Abel
    
    
    
    enoid{at}northwestel.net wrote:
    >
    > I cannot prove this as the person who told me passed away some years
    > ago, however, he was in the military and therefore presumably would have
    > had some insight into the matter.
    >
    > According to my late friend, HO 229 was developed to provide a tabular
    > and manual method of calculating great circle distances and headings of
    > long-range targets.
    >
    > As I said, I can only take the man at his word, and he was a highly
    > reliable and sober source.
    >
    > Robert
    >
    > ----- Original Message -----
    > From: "Royer, Doug" 
    > Date: Friday, January 19, 2007 1:51 pm
    > Subject: [NavList 2095] Re: Just getting started
    >
    >>
    >>
    >>
    >>
    >> For tables either H.O 249 or H.O. 229 or H.O. 214 are all very similar
    >> and 249 is the most convenient but only has a precision of one minute of
    >>
    >> arc which is an accuracy on one nautical mile which is realistic on a
    >> small boat. If you want higher precision, especially for practice
    >> shots while on shore, then 229 or 214 will do.  214 is out of print
    >> but I think its arrangements of the tables is more convenient than in
    >> 229.
    >>
    >> BTW, does anybody know why they switched from the 214 format to the
    >> 229 format so you cant just do a round of sight using only one page as
    >> you could do with 214 but have to chase all over for the LHAs?
    >>
    >> My understanding for the change in format from HO-214 to HO-229 was for
    >> ease/speed of tabular reduction with about the same level of
    >> precision.That may be correct. HO-229 does eliminate a step or two
    >> compared with
    >> HO-214. But then kind of requires the addition of a step when
    >> computingthe double 2nd difference.
    >>
    >> To expand on this further for the new guy's benefit:
    >> I, personally, like using the old HO-214.
    >> HO-249 vol. #1 is quick and easy to use but limits a person to using
    >> only the listed stars. Sometimes those listed stars can't be used
    >> because of local conditions but other, unlisted, bodies that may be
    >> useable can't be included for reduction because there is no data
    >> listedfor them.
    >> HO-249 Vols. #2 and 3 are arranged in the same format as are HO-
    >> 229 and
    >> does away with this limitation.
    >>
    >> If you want a short tabular method H.O. 208 is my preference.
    >>
    >> Good method. My preference is in using HO-211. It consists of 28 pages
    >> of data in one volume which covers it all from anywhere. Easy to use and
    >> quick for obtaining passable results with no limitations on which
    >> bodiesmay be used. For those minimalists in small vessels there is a 9
    >> page
    >> volume of the same method.
    >> You can find many of these books on ebay.
    >>
    >> Or one may download a copy of both HO-208 and HO-211:
    >>
    >> http://www.geocities.com/sadams16/Navigation1.html
    >>
    >> Or the other methods if you desire. I just like having the hardback
    >> volumes of HO-214 thru HO-249 to use but it may not be practical in a
    >> small vessel or if money is an issue the above link will give you the
    >> volumes.
    >>
    >>
    >>
    >>
    >> >
    >
    >
    >
    > >
    >
    
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