NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Proportional logs, etc.
From: Henry Halboth
Date: 2004 Aug 27, 00:03 -0400
From: Henry Halboth
Date: 2004 Aug 27, 00:03 -0400
AH - sooo. Many thanks again, this time to Bruce and Frank, on the
calculation of prologs. I was slowly coming around to the conclusion so
well stated in your postings, but simply could not find support stated in
any written form. Unfortunately, I am still not proving out Brother
Arnold's tables for Sun and Star corrections, but will keep plugging away
at it.
Per Jan's posting, I assume that one could possibly construct a prolog
table for another interval, i.e., 60 minutes, 120 minutes, etc., and
confuse the hell out of the opposition - almost like a code.
Regards.
Henry
On Thu, 26 Aug 2004 19:39:13 EDT Bruce Stark writes:
> Henry,
>
> As for how to calculate proportioning logs:
>
> They are for a three hour interval, and designed to proportion to
> the nearest
> second of time. Three hours contains 10800 seconds.
>
> One hour contains 3600 seconds. So the PL of one hour is simply the
> log of
> 10800/360.
>
> The PL of seven seconds is the log of 10800/7.
>
> The PL of one minute, six seconds is the log of10800/66.
>
> And so on.
>
> Since there are 10800 seconds of arc in three degrees, PL tables can
> be used
> to proportion small angles as well.
>
> Hope this helps.
>
> Bruce
