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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lat. and Lon at LAN
From: Fred Hebard
Date: 2004 Jan 8, 10:10 -0500
From: Fred Hebard
Date: 2004 Jan 8, 10:10 -0500
I'm glad George addressed this question. I had been wondering why he and Herbert Prinz had been saying that noon shots were so bad for establishing LAN, but didn't work through the math as George has. One quibble. With local noon moving at a rate of 15 arc-minutes per time-minute, would not an error of 5 time minutes would put one out 75 arc-minutes rather than 20? I might not mind being out 8 to 20 arc-minutes at the equator but 30 to 75 would be a fair amount. On Jan 8, 2004, at 9:38 AM, George Huxtable wrote: > So there's no way for an observer to time the noon sight within a few > seconds, as Doug claims. If the time of LAN could be determined within > 5 > minutes, then it would establish longitude within about 20 > arc-minutes. Not > a great result. In the unlikely event of a timing precision to 2 > minutes, a > longitude determination to 8 arc-minutes would result.
