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I was looking at the ASA Celestial Navigation Standard (107) the other
day, and noticed that one of their requirements is "Calculate the true
bearing of a low altitude celestial body in order to determine the
error and deviation of the compass".

http://www.asa.com/asa_standards/standard_celestial_navigation.html

Back in the dark ages when I was first learning celnav, the textbook
method for doing compass checks at sea was with amplitude tables and
the sun low on the horizon (at least if I remember right).

I haven't seen amplitude tables in years (does Reed's still have them?)
- but it dawned on me that when you do sight reductions you also have a
true bearing for the celestial object (Zn), so why not just momentarily
point the bow in that direction and note what the compass reads?

Even easier, if you're doing a LAN shot the sun will be either directly
north or directly south of the boat for the time that it "hangs" in the
sky, so that really simplifies the calculations.

Can anyone think of a reason why that wouldn't work as well as using
amplitude tables, or is my info on that method several years out of
date and nobody does it that way any longer?

--
GregR

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