NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Fix by Occultations
From: Dave Walden
Date: 2009 Feb 8, 06:30 -0800
From: Dave Walden
Date: 2009 Feb 8, 06:30 -0800
A nice summary for what's going on from: The Practice of Navigation and Nautical Astronomy By Henry Raper 1882 (google books) "IV. By AN OCCULTATION. 870. The moon in her perpetual revolution round the earth necessarily passes over every star or other body in her path at certain periods. The disappearance of a star or planet, called the immersion, and the reappearance from behind the body of the moon, called the emersion, being instantaneous, the phenomenon affords the means of determining the longitude at all places where it is visible. At the instant of occultation the apparent R. A. of the moon's limb is the same as the R.A. of the star; the effect of the parallax of the moon being removed by computation, the true R.A. is deduced, and the G.M.T. thence found." Then 2-3 pages with rules and examples follow. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
