PROBLEMS 69 
4. With the hour angle (f) and an assumed latitude (use D. R. latitude to 
nearest degree), enter Table I and pick out quantities b, A, C, Z’. 
5. Add algebraically to b the declination obtained from the Nautical Almanac; 
that is, add if the signs are alike, subtract the smaller from the larger if unlike. 
6. With the quantity of d-++b thus obtained, enter Table II and pick out 
quantities Band D. Add B to A and D to C. 
7. With A+B enter column B of this same table (Table II) and find the 
corresponding number. The heading at the top of the column will give the value 
of h, in degrees; the minutes will be found in the extreme left column. 
8. With C+D enter column D of the same table (Table II) and find the corre- 
sponding number. The number at the top of this column will give the value of 
Z’’ in degrees; the tenths of a degree will be found in the extreme right column. 
9. Add the Z’’ to Z’ previously obtained from Table I to get the azimuth. 
This azimuth is always reckoned from the elevated pole and is marked in the 
conventional manner, i. e., north when in north latitude, south when in south 
latitude, east when east of the observer’s meridian, west when west of the ob- 
server’s meridian. 
10. The local hour angle (L. H. A.) is reckoned from the upper branch of the 
meridian westward through 360°. 
' 11. When the lecal hour angie or its explement (360°—L. H. A.) is less than 
90°, give 6 the same name as that of the iatitude (+) if north, (—) if south. 
This is called Case I. 
12. When the local hour angle is between 90° and 270°, give b the opposite 
name to the latitude. This is the Case II exemplified in the problems that follow. 
Tn it the azimuth is always obtained by subtraction. 
When in latitude 0° give 6 the same name as the declination and the azimuth 
takes the name of the declination. ; ; 
NOTES ON SOLUTIONS 
13. It will be noted that in Table [, ¢ is used only to 90° (six hours). The 
manner in which the local hour angle is handled to accomplish this i is simple and 
uniform in all cases. 
(a) If the L. H. A. exceeds 90° W., usc the supplement as t. 
(b) If it exceeds 180° W., reject 180° and use the remainder as ft. 
(c) If it exceeds 270° W., use the explement as f¢. 
(d) If it exceeds 360°, aR 360°, then treat as in (a). 
14. In finding the quantity d+6 with which Table II is entered, should this 
amount exceed 90°, take quantity in degrees from bottom of page and take 
minutes from right-hand column, reading up. .Give the resultant Z’’ a negative 
sign because cot (180°—0)=(—) cote. ,, 
~15. In finding the azimuth when the value of C+D exceeds 10000, as, for 
example 13586, the 10000 is dropped and only the number 3536 is sought in 
Table IT. 
16. In the following examples the letter a is used to-indicate the altitude 
difference (also called intercept) from the assumed position of the observer 
TOWARDS the heavenly body, if the true altitude (h) is greater than the computed 
altitude; away if the true altitude is less than the computed altitude. The 
true altitude (h) =the observed (or sextant) altitude+all corrections applied. 
17. In lieu of a better position the intersection of the perpendicular from the 
dead-reckoning position at the time of the sight to the line of position obtained 
with these tables must be taken as the HSS probable positi 
the line. oe 
