NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Position lines, crossing.
From: Bill B
Date: 2006 Dec 09, 21:58 -0500
From: Bill B
Date: 2006 Dec 09, 21:58 -0500
Peter wrote: > As to George's insistence that the ACTUAL position is not necessarily > located at the centre of a triangle, or other intersecting LOPs, this > does not seem especially helpful. As an example of how unhelpful it > is, Lu is now worrying about the precise statistical improbability > involved. Will this knowledge enable the calculation of a more > accurate position? It is indeed a guessing game and to some degree frustration IMHO. No systematic errors or personal bias, you are *probably* in the cocked hat. No one-in-four statistics as related in my texts. With systematic errors, then you may well be outside the cocked hat according to my texts. I am well aware George is far better read an educated on the topic than I will probably ever be, but it still seems a bit hit or miss in any case. If I have done my homework before a long voyage and do not find personal or systematic problems, or instrument error, then I might tend to believe that after a month at sea that would remain true and trust a position within the cocked hat within certain limitations. That's an assumption. How do you know--really--unless you are comparing to a GPS? I recall a chapter in a book a friend loaned me--I don't recall the title--recounting of a month-long blue-water voyage by some yachtsmen. The author pointed out that such-and-such was their best day yet. They covered 192 miles where yesterday they covered 190 miles. This was done with cel nav and running fixes. No GPS. I had to laugh. Thankfully the sextant can be a bit more precise for coastal navigation, so it serves both purposes very well if taken with a grain of salt and dose of common sense. In the digital age where operating system and application interfaces must be relearned with each upgrade, it is comforting to have a tool in the sextant that meets my classic definition of a tool--a handle on one end and a use on the other. It measures angles well enough for the purpose at hand. The big plus being there are so many uses those angles can be put to. For some tangential reason, UNIX comes to mind. Referring to the various flavors of UNIX, one wag commented decades ago, "A good operating system needs standards, and the beauty of UNIX is there are so many to choose from."Bill --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---