On 7 December your vessel's 0835 zone time DR position is LAT 28°30.0'N, LONG 125°39.3'W, when an azimuth of the Sun is observed. The chronometer time of the sight is 04h 34m 48s, and the Sun is bearing 113° per standard magnetic compass. The chronometer error is 01m 24s slow, and the variation in the area is 13.0°E. What is the deviation of the standard magnetic compass?
Official USCG Answer & Rule Citation
Correct Answer: Option C — 2.3°E
Calculate the Sun's true azimuth using the Nautical Almanac and Sight Reduction Tables. Apply the formula True = Compass + Deviation + Variation. With a calculated True Azimuth of 110.7° and a variation of 13.0°E, the deviation is determined to be 2.3°E to satisfy the compass error equation.
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