NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Latitude from date and length of daylight?
From: Frank Reed CT
Date: 2005 Feb 16, 02:08 EST
From: Frank Reed CT
Date: 2005 Feb 16, 02:08 EST
Nels T you wrote:
"The only problem I can see with this would be in high latitudes,
since
the sunrise and sunset are both very drawn out (if they happen at
all). I wonder if that one-degree-ish estimated accuracy holds in the
high 50's and 60's?"
the sunrise and sunset are both very drawn out (if they happen at
all). I wonder if that one-degree-ish estimated accuracy holds in the
high 50's and 60's?"
Good point. According to an article on their web site, the fish tag
makers provide deduced lat/lon info to their customers, but they do not provide
the algorithm that they use for the calculations. I wonder how much
supplementary data they apply to the problem. For example, do they adjust for
cloudy weather? Do they inform their customers that the latitudes are liable to
greater error under certain circumstances in high latitudes? Maybe we could get
them to describe their calculations for the list...
There is an interesting case study on the web site of a fish that was
tagged and promptly sank to the bottom. It apparently was mortally wounded when
it was caught. Interestingly, a little while later, the fish was resurrected.
The tag began to record changing temperature and depth data but no light levels.
So it was swimming, but in total darkness. This continued for days,
and after that the tag bobbed to the surface and began recording
night/day light levels again. They theorize that the recently deceased
fish was eaten by a shark, tag and all. And it's dark inside a shark! Later
the shark got the tag out of its stomach one way or another.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars