On 16 April in DR position LAT 28°07.0'N, LONG 81°47.0'W, you observe an amplitude of the Sun. The Sun's center is on the visible horizon and bears 073.5°psc. The chronometer reads 10h 53m 41s and is 02m 23s slow. Variation in the area is 11°E. What is the deviation of the magnetic compass?
Official USCG Answer & Rule Citation
Correct Answer: Option A — 6.5°W
Celestial amplitude computations convert chronometer time to Greenwich Mean Time, extracting solar declination from the Nautical Almanac to find the true bearing, which is then compared against compass readings and variation.
100% Free & Open Access — No daily limits, paywalls, or gated answers on BrightMariner.