At 1318 ZT on 10 September, in DR position LAT 24° 05.8' N, LONG 058° 08.3' E, you observe an amplitude of the Moon. The upper limb of the Moon is on the visible horizon and bears 254° psc. Variation is 2° W. What is the deviation?
Official USCG Answer & Rule Citation
Correct Answer: Option C — 4.0°W
Upper limb moon amplitudes demand correcting the observed horizon bearing for semi-diameter and parallax. Compute true bearing from tabular data, apply variation, and extract deviation.
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