NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Ocean Yachtmaster Exercises
From: R B Emerson
Date: 2008 Aug 17, 23:12 -0400
From: R B Emerson
Date: 2008 Aug 17, 23:12 -0400
First things first, I was wrong in my comments about moving LOP's by the amount of the index error or index correction. Nonetheless, the concept raised a major "Not A Good Thing" flag when I read the first post in this topic. And now I remember / understand why. It's one of those things that is best be described as "right for all the wrong reasons". Can the LOP's be tweaked by the amount of the index error with opposite signs (in this case 4.0' or 4.0 nm)? Running through the reductions with both Ic's shows the answer fast enough - so much for the "right" part. Split the difference and there are the error-free LOP's. But at the same time, the plotting sheet starts to look pretty ratty as (in this case) four LOP's become a total of 12 LOP's, six of which are in error. And this is the "for all the wrong reasons" part. What's on the sheet should be clear, as accurate as possible, and presented in such a manner that a complete stranger could read the story, presented on the sheet, without having to ask the author, "why is this here and what is that doing over there?". Fudging LOP's after remembering there was an error in handling index error during reductions is a (IMHO large) step away from clarity. It also opens the door for more error; are all LOP's "fudged", were some right and moved by mistake, or... the room for Murphy's Law expands a little too readily. So I'll amend my summary comment to "You just shouldn't do it". Rick Emerson S/V One With The Wind --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
