Mark wrote And, as others have pointed out, the position of the moon also gives a clue. Craig wrote: But this is useless for determining longitude because all you can measure is high noon. G'Day Craig and Mark, Two methods tried were one based on an idea of Galileo's that used Jupiter's moons. This was impractical as it could be flawed by the slightest inadvertant movement, and a second called the lunar distance method developed by Johannes Warner, which the Astronomer Royal Maskelyne used successfully on a voyage to St Helena. In the lunar method you read the time when the moon was adjacent to a star or a series of stars and compared local time against tables of standard times of the same measurements at a reference location. These tables might have been the origin of the 48 books you mentioned earlier? Both methods had the effect of reducing the need for maintaining a clock's accuracy over weeks or months, but I don't know how accurate the measured time had to be. Then there was the barking dogs and sympathetic powder, an obvious method to "the prepared mind":~) All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Thu Jul 29 2010 - 14:49:48 PDT
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