NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Z tangent formula
From: John Simmonds
Date: 2005 Jul 7, 19:46 +1000
John
>snip<
>
>?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?
From: John Simmonds
Date: 2005 Jul 7, 19:46 +1000
Actually, I would suggest that the Sharp nav calculator uses the same formula, truncated to 1 decimal place :)
John
live every day like it may be your last .. cause one day it will be
>snip<
>
>?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?
