Next message: Peter Fogg: "Re: Z tangent formula"
At 08:42 07/07/2005, Peter Fogg wrote:
>I've taken 3 sights at random to contrast a few different (?) methods of
>azimuth determination. The first comes from the problem Mike Burkes posed,
>that I worked out and posted here on the 2 July.
>
>Sun UL Azimuth - in decimal form, and to 3 decimal places if available
>101 'Bennett book' azimuth tables
>100.9 Sharp nav. calculator
>100.982 NavPac
>100.985 Z tan formula
>
>The other two come from the first other worked sights to hand. Details
>available if anyone's interested.
>
>Miaplacidus Azimuth
>183 'Bennett book' azimuth tables
>182.6 Sharp nav. calculator
>182.637 NavPac
>182.665 Z tan formula
>
>Dubhe Azimuth
>010 'Bennett book' azimuth tables
>010.2 Sharp nav. calculator
>010.238 NavPac
>010.214 Z tan formula
>
>So I'm convinced, pending further tests, that the Z tan formula is a valid
>and accurate method for determination of azimuth. The small differences seem
>insignificant. It is not significantly more tedious or time consuming to
>calculate, given a good scientific calculator, than the other methods. This
>is because the calculator and NavPac require quite a lot of data to be
>entered to give a result.
>
>However, I do wonder whether one method or another does give a more
>precisely accurate result, although the answer is probably irrelevant for
>most practical purposes. Am hampered, admittedly, by not knowing what
>methods my calculator or NavPac use. Anyone have other formulas for
>comparison purposes? Or ideas on this?
But Peter makes it difficult (indeed impossible) for anyone else to
reproduce his calculation, by omitting mention of the values of hour-angle,
lat, and dec that he has used. If Peter will provide that missing-link, he
might get some more informed responses.
George.
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Contact George at ,or by phone +44 1865 820222,
or from within UK 01865 820222.
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