Sextant accuracy with short distance to horizon
Subject: Sextant accuracy with short distance to horizon
From: Richard B. Emerson (navsys@XXX.XXX)
Date: Thu Jun 21 2001 - 10:47:08 EDT
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
