A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ed Popko
Date: 2019 Dec 23, 04:09 -0800
Frank has done a nice job of explaining MOO and MOB. The MOO umbrella image with it's celestial motion axis normal to the course of the vessel is a nice visualization.
Gary La Pook first wrote about MOO and MOB some years ago when explaining the fundamental differences between nautical and aero navigation. His explanation, "Celestial up in the Air" is an important NavList archive post. Look for it. Tracy Shrier provides additional MOO and MOB examples when correcting bubble sextant shots taken from a fast moving jet airplane. The challenge is to correct a round of sites to a common fix time. Tracy employed the MOO MOB scales on the Polyhmus Computer circular slide rule. See NavList archives.
Attached is a text file of test cases. The speeds are fast moving jet planes but they demonstrate typical MOO situations. Both advancing and retarding examples are given. These are personal test cases for my calculator programs. Hopefully there are no errors. (famous last words!)