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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Green Flash and Longitude
From: Frank Reed CT
Date: 2006 Jan 5, 17:50 EST
From: Frank Reed CT
Date: 2006 Jan 5, 17:50 EST
Bruce Stark, you wrote: "To my knowledge, no history of navigation has yet been written by anyone who's at ease in that way of thinking. I hope you'll consider writing such a history yourself. " Consider it? Yes. Even wrote quite a bit. Finish it?? Well, that depends on whether I can think of a way to make it profitable --in a broad sense of the word. And: "Anyone hard wired in the twentieth century way of thinking will immediately see that by noting the time of a Green Flash (should you be so lucky as to see one) you'd have the makings of a longitude LOP. How accurate it would be is another question." Clearly it would not be particularly accurate --no more so than any other sunset/sunrise LOP which means +/-5 or 10 minutes of arc error in the resulting line of position. Could I ask you to clarify something for me: have you yourself heard of this before? Have you heard or read that the green flash can be used to determine longitude (or at least a more or less north-south LOP)? Do you remember the context of the discussion? Finally, do you recall any reason why someone would have suggested using the green flash specifically, which is quite rare, instead of timing an ordinary sunset? -FER 42.0N 87.7W, or 41.4N 72.1W. www.HistoricalAtlas.com/lunars