NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Landlubber Sunrise Table
From: Joe Schultz
Date: 2009 Oct 29, 04:25 -0700
From: Joe Schultz
Date: 2009 Oct 29, 04:25 -0700
I don't really have a need for a nautical almanac or tide book when travelling on land, but I do like to plan the trip to maximize daylight. The attached Sunrise Green Bay.pdf is built for the latitudes of "the lower 49" in the US, and includes a worked example. First page is the table for 2010 (data from U.S. Naval Observatory website), built in Microsoft Excel software. Those who use tide books will recognize the format. Added the longitude table and minute-to-degree table at the request of others. I usually scribble the solution on this page, then erase it before the next calculation. Second page was built out of frustration on my part. It seems this semi-graphical solution is the trick, as far as a beginner learning the process. Latitude and longitude degree scales are subdivided in 10min intervals, and the F scale is subdivided in 0.02 intervals. Pick the wrong time zone meridian and the assumed longitude won't plot - self-correcting in that respect. In the U.S., these two pages will print for 20 cents at a FedEx/Kinkos store. Third and fourth pages are a solved example, showing a lot of work that I do on my fingers. My solution is a minute off the U.S. Naval Observatory's website solution. Question for the math wizards: is there a way to nomogram the latitude correction directly from the linear F scale? If so then I can eliminate the multiplication boxes and reduce the graphical solution to addition and subtraction. Tried making the latitude scale logarithmic but it looks too strange for the beginner. Critiques and ideas are welcome. Thanks, Joe --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com -~----------~----~----~----~------~----~------~--~---