PROBLEMS ia 
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REDUCTION TO THE MERIDIAN 
(Near meridian) 
The method of finding altitude and azimuth as set forth in these tables is 
accurate to the time of meridian passage when the altitude of the observed body 
is less than 75°. 
When a sight is reduced to the meridian, the resultant latitude is not the 
latitude at meridian passage, but is the latitude at the time of taking the sight. 
(See Bowditch, 1933, art. 330.) With this method a line of position is quickly 
obtained; and, should the intercept be sufficiently small and the azimuth close 
to 0° or 180°, we have practically a latitude line of position at the time the sight 
is taken. 
Problem 12.—On June 26, 1928, about noon, the U.S. 8. S—2/ in lat. 21S. long. 
60° E., by D. R. observed altitude of sun’s lower limb bearing northeastward, as 
follows: Watch 115 38™ 35s, C-W. 7» 59™ 10s, chron. slow 0™ 108. True altitude 
45° 0’ 0’’. Find position line. 
h m 8 
Ny je Hits saeco 
CaWe ene ok CY ® 
(Cin BR a ee eee “3 45 
(Go! Ces, salen een 10 
Gis Os Mt, BH dramas 7 Be HS 
Highoneys—=2(—) 235 
A ee 7 35 20 (add 24 hrs.) 
Subtract. -=—- 2 12 
(aR AG ee 19 35 20 W. 
UAT CE Spe Sa: SO 293° 50 W. 
Monee H.28 (+) 60° 10’ BE. 
eH VA ok Sue 354 00 W. (subtract L. H. A. from 360°) illustrates 
Orgs He wAses. 8 6° E. Note 13(c). 
PENGo dss. eee DBS). COMIN 
ESQ NODE 2 esses 68 53.7 S. A 208 C 1011 Z’ 87.8° 
d+6b 45 31.2 B 14661 D 9992 
h-=45° 14.5’ A+B 14869 | C+D 11003 Z’ 84.3 
= ° ? ee 
Wee OU (reject 10000) see Note 15. % 172°1 S.and E. 
a= 14.5’ away 
The true latitude is on the position line at a point in the correct longitude. 
IDENTIFICATION OF AN UNKNOWN STAR 
Refer to Figure 1, page 67. In the problem of finding the altitude and azimuth 
there is given two sides (d and L) and an included angle (é) of a spherical triangle 
and it is required to find the third side (h) and one other angle (Z). In the prob- 
lem of identifying an unknown star, there is given two sides (L and h) and an 
included angle (Z) and it is required to find the third side (d) and one other angle 
(ft) with which to find the body’s right ascension. The problems are therefore 
similar; and, if in the tables we interchange Z for t, and h for d, we may readily 
identify the unknown body. 
