| |
Azimuth of the Sun, Continued
Look at the left-hand column of the stip form below. Notice that you’ll find
values for Dec. Inc/Z Diff, Lat Inc/Z Diff, and LHA Inc/Z Diff. This is
where we enter the leftover values from our whole degrees of DR Lat,
Declination, and LHA. To do this, we must convert our leftover values into
tenths of degrees by dividing each by 60 and rounding to the closest tenth of
a degree. Finding Z Diff is a matter of inspecting Pub 229 (see figs. 9-3
and 9-4) in the following manner:
For Dec Inc/Z Diff note the values for the whole degree of dec that you entered the table
with and the next high dec, then find the difference. Here are the values for our example
problem: Dec 19° Z = 129.1 Dec 20° Z = 129.8. The difference between the values is 0.7.
Since the value is increasing between 19° and 20°, we assign it a positive value (+).
Repeat the same procedure for finding Z Diff for Latitude and LHA. In other words,
compare lat. 33° and lat 34°. Then compare LHA 51° and 52°.
OPNAV 3130/
Azimuth by 229
ACTION
Completed Strip
Form
Tab Z
Enter Pub 229 with entering arguments of
Lat 33°, LHA 51°, and Dee 19°. Make
sure that you enter on the portion of the
page that indicates LATITUDE
CONTRARY TO DECLINATION.
Follow 19° of Dee across the page to where
it falls under the 33° Latitude column and
record the value for Tab Z.
Dec. Inc (left) = 31.6' + 60 which = .53
rounded to 0.5. Compares Z’s for Z Diff.
Multiply Dee Inc by Z Diff.
Lat Inc (left) = 37.0' + 60 which = .62
rounded to 0.6. Compares Z’s for Z Diff.
Multiply Lat Inc by Z Diff.
LHA Inc (left) = 53.4' + 60 which = .89
rounded to 0.9. Compares Z’s for Z Diff.
Multiply LHA Inc by 2 Diff.
Drop the Dec Corr Down.
Drop the Lat Corr Down.
Add the LHA, Dec, and Lat Corr.
129.1
Dec Inc/Z Diff
Dec Corr
Lat Inc/Z Diff
Lat Corr
LHA Inc/Z Diff
LHA Corr
Dec Corr
Lat Corr
Total corr
0.5 / + 0.7
+ 0.35
0.6 / + 0.3
+ 0.18
0.9 / - 0.7
- 0.63
+ 0.35
+ 0.18
- 0.10
We have now accounted for our leftover values and now can find the Exact Z.
9-7
|
