NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Arg 1 Ww 11 U Boat Navigation Device Ebay Item Number: 370193239339
From: Dave Walden
Date: 2009 May 28, 04:58 -0700
From: Dave Walden
Date: 2009 May 28, 04:58 -0700
The use, as explained by gl and his attachments, is simple. Set the index mark on the clear overlay to 90 degrees North. Put a mark on the overlay at the body's LHA and Dec. Rotate the index mark to the observer's Lat, read Alt and Zn. That's it! Creating the plot involved an interesting side trip to Wolff nets, crystallography, "East Poles" and projections. Google image "Wolff net" for some already made up. Google web "Wolff net" for Wolff and diffraction origins. Wikipedia has equations; check "stereographic projection". A helpful web site was: http://journals.iucr.org/iucr-top/comm/cteach/pamphlets/11/node4.html A spreadsheet for playing with the projection, and a FORTRAN program to generate the diagram are attached. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
File: 108425.stereographic.xls