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From: Jim Thompson (no email)
Date: Wed Sep 03 2003 - 05:45:47 EDT
This is a "newbie" question. I am learning celestial navigation. What is
the convention for plotting 3-body fixes taken within a few minutes of each
other? Say I take 3 sights on 3 stars, on a moving vessel, all within a
span of 15 minutes.
Method A:
1. Work out DR positions for each of the sights (L, Lo).
2. Use the L and Lo for each sight's DR to work out the intercept, azimuth
and LOP for that sight.
3. Advance the LOPs for the first two sights to the last DR to draw the
cocked hat fix estimate.
Method B:
But the Canadian Power and Sail Squadrons' course manual implies a different
method, although I am reading between the lines to operationalize what they
wrote:
1. Work out DR positions for each of the sights (L, Lo).
2. Use the L and Lo for each sight's DR to work out the intercept, azimuth
and LOP for that sight.
3. Simply plot the LOPs for for all 3 sights from the last DR to draw the
cocked hat fix estimate (without formally advancing the 2 earlier LOPs).
Jim Thompson
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