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Azimuth of the Sun, Continued
Gathering Data
Now that we have three good observations, we need only to find the DR
position for each obvservation to have the data we need to find the
azimuth of the Sun. We will work an example problem using OPNAV
strip form AZIMUTH BY PUB 229. For brevity, we’ll work on one
observation only. In actual practice, it’s faster to work out all three at
the same time by placing the strip form on the left and working the
three observations in the next three columns. The purpose of taking at
least three observations is to allow us to find errors when taking
observations and averaging gyro error. This process normally provides
the best results in determining total gyro error.
Besides the data from the observation, you’ll need the Nautical Almanac
and Pub 229 to solve the problem.
From the strip form and publication we will find out exactly what the
gyro bearing should read, then we will compare that value to the actual
gyro bearing from the observation. The result will be our gyro error.
Example
Problem
For our example problem, we will assume that we have gathered the
following data:
Date:
19 Nov 84
DR Lat.:
33° 37' N
DR Long.:
112° 39' E
ZT:
15h 42m 22s
Gyro Brg:
231.6°
On the following pages, you will find the page laid out with the blank
strip form on the left, the action steps in the middle, and the result on
the right.
9-3
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