NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Interpolation to latitude
From: Joe Schultz
Date: 2009 Nov 12, 13:01 -0800
From: Joe Schultz
Date: 2009 Nov 12, 13:01 -0800
Hi George, Sorry about the delay - was busy with the American Veteran's Day holiday. I'm going to answer in a 'round-a-bout way; the intent is to not confuse Inuik. This is his series of postings. 1. We no longer operate in an LMT world, and very few living people remember what that was like. Instead, we operate in a zone time world. As an example, I listen to BBC radio news. They always state the time in GMT. I then mentally subtract six hours to get my local zone time, then glance at my watch (to confirm my sums). It's a natural process for me because I've never lived in an LMT world, and I see no reason to switch worlds when navigating. I fail to understand why the navigation schoolbook authors want us to switch back and forth and, in my opinion, they are confusing their readers. 2. The daily pages of a paper nautical almanac are very elegant. Enter the daily pages with approximate time (left side) or position (right side), then extract position (left) or time (right) data. Then apply some form of latitude and longitude corrections to get "exact" position or time. And the daily pages operate in a zone time world, just like we do in our daily lives. My solution method for Inuik's exercise takes advantage of both statements. No need to bend our minds around the concept of operating in an LMT world. The attached Inuik_2.gif is my complete solution. Inuik, get ready. I'm going to ask you "why is it OK to interpolate for the LAT CORRN?" But I'll wait until you tell me that you understand how to apply the LON CORRN. And don't hurry. If you get a good handle on these calculations then the rest of the almanac's daily page will fall into place for you. Joe --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com -~----------~----~----~----~------~----~------~--~---