NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: About Lunars, part 3 (correction)
From: George Huxtable
Date: 2002 Feb 15, 23:42 +0000
From: George Huxtable
Date: 2002 Feb 15, 23:42 +0000
In my reply to Chuck Griffiths, sent a few minutes ago, there was an error which needs correcting. What I said was- "Try this out on a globe of the world, in exaggerated form. Forget about the continent-markings on it, we aren't using it as a model of the World, just as a sphere to show up the spherical geometry. In fact, we only need the upper hemisphere. The equator represents the plane of the observer's horizon, and the observer is at the centre of the globe. Mark a spot at say zero longitude, 30 N latitude, and another at 90 longitude, 30N latitude. These spots represent the two stars, in GHA and altitude. Measure the distance between the spots (the interstellar distance) with a piece of string, along the shortest path (a great circle). This length corresponds to the length of the ars between the two stars as seen by the observer..." ===================== Where I referred to the spots representing two stars "in GHA and altitude", I should have said "in azimuth and altitude". The globe, as a model, makes more sense that way. Oh, and where I aid ars, it should have been arc, of course! Sorry about that. George. ------------------------------ george@huxtable.u-net.com George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. Tel. 01865 820222 or (int.) +44 1865 820222. ------------------------------
