A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Geoffrey Kolbe
Date: 2015 Nov 4, 09:50 +0000
To the Lunatics
Herein lies a difficulty.
Assume a star directly in the path of the moon, such that the star (at immersion) bisects the northern and southern orb. The star is then immersed at the semi diameter (radius) of the moon.
Now assume that a star, upon immersion, is occluded by the Northern tip of the orb. That is, the moon occludes the star at +85° of its latitude. The immersion does NOT occur at the semi diameter of the moon along its path. Rather, it occurs at cos(moon's latitude of occultation)*SD, in this case cos(+85°)*SD.