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Subject: Re: cosine/haversine method
From: Chuck Taylor (ctaylor@XXX.XXX)
Date: Sun Feb 11 2001 - 00:47:50 EST
Russell Sher wrote:
>
> Does anyone have much experience using the cosine/haversine method of sight
> reduction? As I understand it, this will calculate Hc, after which the
> azimuth has to found using tables or formula. I am interested in finding
> some suggestions on what is perhaps the easiest way to find Zn (or Z)...
> (ABC tables, formula etc...)
Russell,
The traditional way, per the 1943 Bowditch, was to use the formula
sin Z = sin t * cos d * sec h
which was worked out with tables of the logarithms of the various
trigonometric functions. With a modern calculator, this would be
equivalent to
sin Z = (sin t * cos d) / (cos h)
Chuck Taylor
Everett, WA, USA
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