NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2013 May 3, 20:07 -0700
| Yes you can use any method you like to compute the altitudes at twenty minute intervals and then plot the precomputed altitudes on graph paper so that precomputed altitudes for intermediate times are instantly available. HO 218 is the forerunner to HO 249 and it is divided into two sections, with one section for selected stars. You get similar results with HO 214, HO 249, HO 229 and the short trig methods, HO 208 (Noonan's favorite) and the Weems Line of Position Book. . You can also use th Bygrave slide rule and HO 211 which allow you to use the destination directly as the AP while using the other methods require a selected AP and then an adjustment to convert the computed altitudes at that AP to the altitudes at the destination. This can be done graphically, as stated in NIF using HO 218, or mathematically as done with the correction tables for HO 214.
See attached files and: http://www.fer3.com/arc/img/105707.ho214-delta%20lat.pdf If you don't have HO 214 you can figure out your own "delta t "values since they are simply the difference between tabulated altitudes in HO 218,Ho 249, (or HO 229 not as conveniently) for successive values of LHA. gl --- On Fri, 5/3/13, Bill B <billyrem42@earthlink.net> wrote:
|
