NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Sextant accuracy with short distance to horizon
From: Richard B. Emerson
Date: 2001 Jun 21, 8:47 AM
From: Richard B. Emerson
Date: 2001 Jun 21, 8:47 AM
Dan Allen writes: [...] > This led me to think more about possible inaccuracies of using a horizon > that is very close rather than naturally far away. That is, typically you > use a horizon that is at the limit of your vision, perhaps 20 miles away. [...] While you're in Bowditch, check out table 12, "Distance of the Horizon". Assuming you're 6' tall and standing on a deck 4' off the water, for a total height of eye of 10', the horizon is 3.7 miles off. A twenty mile horizon requires a height of eye of something like 300'. And clear air. [grin] Rick S/v One With The Wind, Baba 35