NavList:

Earlier this evening, Hanno Ix and I were discussing a method for finding longitude that was used historically by land-based astronomers. You time the difference between the transit of the Sun and the transit of the Moon (either the leading or trailing limbs of each body). How accurately could you do this with simple tools and basic math today? Does it depend on an exact meridian observation, or if we're a degree or two out of line with the true meridian (but the same for both bodies) can we still get an accurate longitude? And can anyone point us to a write-up of this technique from the early 19th century? Is it in Chauvenet somewhere? Observations like this were certainly used to get longitudes of observatories in remote locations in the era before the telegraph. Anyone else interested in resurrecting this technique? --just for fun, of course!

-FER
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