A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2011 Jan 15, 16:43 -0800
|H.O. 229 takes up a lot of space and is heavy and provides more precision than is actually needed for small craft navigation. H.O. 249, Sight Reduction Tables for Air Navigation, is much more compact and the arrangement of the tables is more convenient. Both tables are used the same way (with the exception of the second differences correction for slightly greater accuracy for high altitude sights in H.O. 229 that you can skip if you choose) so if you can work one set of tables you can work the other. I suggest you download H.O. 249 from this site:|
(click on "Publications")
print out a few pages and compare with your H.O. 229.
You can check your work by having the Navy do the computations here:
Since you are just getting started, and before you head gets polluted with these other complicated methods, I suggest you try the flat Bygrave slide rule which you can make for yourself at a cost of a few dollars with the printouts available here:
The Bygrave computes everything your need in less than two minutes and uses no batteries.
--- On Sat, 1/15/11, Patrick Goold <email@example.com> wrote: