NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Feb 9, 14:31 -0800
David Pike, you wondered:
"What did you mean the sun is so low it makes the use of an artificial horizon impractical?"
I believe he said that the Sun is so far south that it makes the use of an artificial horizon impractical. But you see... he is in the southern hemisphere, so a far southerly declination for the Sun actually implies that the Sun is too high for an artificial horizon. Assuming a sextant has a maximum practical angular measurement of 120° (some manage a bit more but we'll ignore that), that implies a maximum altitude of 60°. How did 19th century explorers/surveyors in Africa and Australia, for example, measure latitudes on land with a sextant when the Sun at noon was higher than 60 degrees?
Frank Reed
ReedNavigation.com
Conanicut Island USA
