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On 31st Aug 2008, AM at ship in DR 40˚ 30’N 064˚ 56’E, the sextant altitude of the star DIPHDA was 21˚ 28.4’ when the chron (error 01m 06s FAST) showed 00h 21m 32s. If IE was 0.9’ off the arc & HE was 09m, find the direction of the LOP and the intercept.
GMT 31 Aug 00h 20m 26s
GHA Ȣ(31d 00h) 339˚ 32.7’ Dec S 17˚ 56.1’
Incr. (20m 26s) 005˚ 07.3’ Lat 40˚ 30’ N
GHA Ȣ 344˚ 40.0’
SHA * (+) 348˚ 59.1’
GHA * 333˚ 39.1’
Long (E) (+) 064˚ 56.0’
LHA * 038˚ 35.1’
P = LHA
= 38˚ 35.1’
We know that :
Cos CZD = ( Cos P × Cos Dec × Cos Lat) + ( Sin Lat × Sin Dec )
Cos CZD = ( Cos 038˚ 35.1’ × Cos 17˚ 56.1’ × Cos 40˚ 30’ N ) + ( Sin 40˚ 30’ N × Sin 17˚ 56.1’ )
CZD = 68˚ 33.6’
Sext Alt 21˚ 28.4’
IE (OFF) (+) 00.9’
Observed Alt 21˚ 29.3’
Dip (HE 09m) (-) 05.3’
App Alt 21˚ 24.0’
T Corrn. (-)02.5’
T Alt 21˚ 21.5’
TZD 68˚ 38.5’
TZD = 68˚ 38.5’
CZD = 68˚ 33.6’
Intercept = 4.9’ AWAY
Azimuth = S 39.6˚ W
T Az = 219.6˚ (T)
LOP = 129.6˚ – 309.6˚
