NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Dreisonstok Compliments Weems
From: Greg Rudzinski
Date: 2009 Dec 14, 12:50 -0800
From: Greg Rudzinski
Date: 2009 Dec 14, 12:50 -0800
In the process of comparing short methods of non electronic sight reduction it came to my attention that the subtle differences between Dreisonstok and Weems tables actually compliment each other very well thus making it worth while having both copies at hand. The beauty of having both lies in the treatment of declination as a plus or minus. What I like to do is add instead of subtract where ever possible so by using Weems in the northern hemisphere fall/winter and Dreisonstok in the northern hemisphere spring/summer addition of declination is maintained. The other beautiful compliment is the graph vs. tabular azimuth determination. When speed is needed then the Weems graph is used. When accuracy for compass error determination is needed then Dreisonstok is used. Once an Hc is determined by Weems then extracting Z' and Z" from Dreisonstok is simple. -- NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com
