A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2021 Jul 20, 13:18 -0700
David Iwancio you wrote: you can't determine the hour angle of a body from latitude 90° because you don't have an hour angle.
Are you quite sure about that? The celestial body has a sub-stellar point somewhere other than the Pole. It has a declination and a Greenwich hour angle (GHA Aries + SHA) or a right-ascension, whichever you prefer. True, LHA becomes a bit meaningless, but you don’t need LHA to plot a position line from an assumed position at the Pole. You just need to know which meridian the body is on at the time of the observation, and all the meridians are shown on a polar projection. It falls into the same bag of tricks as meridian passage and polaris observations. DaveP