On 9 May your vessel's 1809 ZT DR position is LAT 48°13.7'N, LONG 168°36.3'E, when an amplitude of the Sun is observed. The Sun's center is on the celestial horizon and bears 283.7° per standard magnetic compass. Variation in the area is 13.0°E. The chronometer reads 07h 13m 19s and is 02m 56s fast. What is the deviation of the standard compass?
Official USCG Answer & Rule Citation
Correct Answer: Option D — 0.1°W
Calculate the Sun's declination and LHA to find the True Amplitude. The True Amplitude compared to the compass bearing gives the Compass Error. With a variation of 13.0°E, the deviation is derived by subtracting variation from the Compass Error, resulting in 0.1°W, as per standard celestial navigation procedures.
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