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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: from a watcher
From: Mike Burkes
Date: 2002 Oct 17, 22:01 -0700
From: Mike Burkes
Date: 2002 Oct 17, 22:01 -0700
From Mike,PS: The good old sin-cos of Hc is pretty hard to beat as you are well aware!
----- Original Message -----From: Robert EnoSent: Thursday, October 17, 2002 8:42 PMTo: NAVIGATION-L@LISTSERV.WEBKAHUNA.COMSubject: Re: from a watcherI feel compelled to comment on the following (clipped)
----- Original Message -----
From: Dan Allen <danallen46@ATTBI.COM>
To: <NAVIGATION-L@LISTSERV.WEBKAHUNA.COM>
Sent: Thursday, October 17, 2002 9:52 PM
Subject: Re: from a watcher
> Note that the US nautical almanacs have a set of sight reduction tables
> in them already so you actually only need one the volume if you do not
> have a strong preference for a different set of tables. Here again the
> whole point of sight reduction is solving one formula:
>
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I do not recommend relying on the sight reduction tables in the Nautical
Almanac. They are, in a word, difficult. I know because I tried and every
time I thought that I had it aced, I'd end up making some really silly
mistake. The tables are just too complex and require too many steps which
opens one up to all kinds of errors.
Better to stick with something simple and easy: HO 249 or even HO
211(Ageton) although you do need a form for the latter tables. In the end,
I'd go with a good $25 solar-powered calculator. They are very easy to keep
clean and waterproof (a zip lock bag) and it is much easier to manipulate
the spherical trig functions than fumble with complex tables.
Please note that I am not denigrating these tables. I believe that they were
designed by Admiral Davies, USN, who was not only a great navigator but a
brilliant mathematician. Unfortunately, most of us are not so well endowed
in the cerebral department.
Keep it simple I say.
Robert