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I am working on the book "Practical Celestial Navigation" by Susan P. Howell
and I have a question about one of the exercises in the book.
Specifically, in exercise 7 problem 5, the altitude and azimuth calculated
for the Sun LL sight given by the answer in the back of the book
disagrees with my calculation. However, if I recalculate it with an
assumed latitude one degree higher, I get the answer in the book.
What am I doing wrong?  Here is the problem:
The 1500 DR is at 36 deg 20' N and 156 deg 16' E.
W.E. on Z.T. is 47 sec fast. Height of eye is 6 feet, I.C. is 0.
The Sun LL sight at W.T. of 12-16-13 is Hs=73 deg 39.7'
Local date is 6-Jul-76
A summary of my calculations follows:
GMT 02-15-26
Date 6-Jul-76
GP of the Sun is GHA 212 deg 41.7, Dec = 22 deg 41.3 N
AP used is 36 deg N, 156 deg 18.3' E.
LHA is 9 deg
Ho is 73 deg 53.0'
The intercept from HO 229 is 40.9 Nm away at 212.9 deg.
If I use an assumed latitude of 37 deg N, then I get
a = 10 nm T at 211.1 deg. which is the answer given in the book.
Any comments?
Sam Chan

   

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