NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: mid-longitude sailing
From: Bill B
Date: 2007 Jan 09, 21:26 -0500
From: Bill B
Date: 2007 Jan 09, 21:26 -0500
George wrote: > I haven't come across that method before. It seems a simple way to > split up a long ocean passage. It's exact, not an approximation, and > it does seem to give the right amswers. Can anyone see snags? Outstanding George, and simple. Thank you for an excellent contribution. Snags? The obvious--cosine or tangent of 90d. I imagine a bit sketchy in areas approaching 90d with a pocket calculator. I did play with departure and destination latitudes approaching zero and those seem to be a wee bit off at first blush. I need to compare that to other methods of calculation before I can say for sure. If there is a difference, I don't know how much is contributed by the use of a pocket calculator. At any rate, I don't foresee that situation as a problem in the practice of real-world sailcraft navigation. The method seems to accept conventional signing of north and south latitudes, and east and west longitudes without so much as a hiccup. Under the category of "small things amuse small minds" it was so simple I could not resist playing with equal departure and destination latitudes 1' and 1" north of the equator, with longitude difference approaching 180d. Fun and interesting to see at which point it routed me over the pole instead of along an equatorial path. Bill --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---