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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@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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