75 USE OF THE TABLES 
Azimuths are reckoned from the north in north latitude, and from the south 
in south latitude, from 0° to 180° to the east and west of the meridian, so that 
for any azimuth over 90°, Table I is entered with the supplement, then the sign 
of b, and ¢’ (used as Z’), become negative values. h is always positive. If h+b 
is algebraically negative, then dis named contrary to latitude, and t’’ (used as Z’’) 
isminus. tis the hour angle named from the initial point north (0°) to the east 
or west, to agree with the observed bearing of the star. When the algebraic 
sum of ¢’, and ?’’ (to give #), is negative, subtract it from 180°; the remainder is 
the hour angle ¢, east, or west, of the meridian. 
Problem 13.—The U.S. 8S. Lardner is making passage from Colon to the United 
States. During evening twilight on October 7, 1928, while in D. R. position 
latitude 15° 05’ N., longitude 76° 40’ W., a star is observed through a break 
in the clouds and the following data recorded: W. 64 06™ 208; C-W. 5 10™ 06s; 
chronometer fast 10™ 065, h, 20° 55’; I. C. (+)1’; height of eye, 36 feet; bearing 
of star by gyro, 285° (N. 75° W.). Identify the star. 
With Z=75° (used as #) and L=15° enter Table I. 
h=20° 47!6(+) 
b=44° 0'4(+) <A 44389 C 30 2? 46°0 
h+bd 64° 48/0(+) B 4343 D 9673 
dec. 19° N. A+B 48732 | C+D 9703 ?’’ 26°8 
t=72°8=4 51™ west of merid- 
ian, since 4=285°. 
h m 8 
1 ae es eR 6 06 20 
AW ceo ee 5 10 06 
Il 16 26 
(CAR Coane. Sa ane (—) 10 06 
Gs C.D. 7 Oct. 23 06 20 
Le. Ce ae aa 1 O1 33.8 L— ~ 
1] 6 SA ne Rep ce Bis Bh. * Bi 
CES ad Saag pe eae ay i 24 11 41.5 
WON ee (—) 5 06 40 
PPS. Butera. NN 19 05 01.5 M 
(Approz,)i 2222-22282 4 51W 
(Approx,)- Ry Al os 2222 14 14fWith these enter the Nautical Almanac. 
(Approx.) dec______ (+) 19° Star is identified as Arcturus. 
Problem 14 (here Z is over 90° hence 6b and ?#’ are negative).—The U. 8. 8. 
Argonne is making passage from Midway Islands to Shanghai. During evening 
twilight on July 20, 1928, while on D. R. position latitude 28° 18’ N., longitude 
179° 47’ W., an unknown star is observed and the following data recorded: 
W. 7» 16" 24°; C—W. 115 52™ 208; chronometer slow 7™ 288; I. C. (—) 1’; 
height of eye, 41 feet; h, 22° 58’; bearing by gyro 91° (south and east). Identify 
the star. 
