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?

Question

On 9 May your vessel's 1809 ZT DR position is LAT 48&deg;13.7'N, LONG 168&deg;36.3'E, when an amplitude of the Sun is observed. The Sun's center is on the celestial horizon and bears 283.7&deg; per standard magnetic compass. Variation in the area is 13.0&deg;E. The chronometer reads 07h 13m 19s and is 02m 56s fast. What is the deviation of the standard compass?

Accepted Answer

Option A: 0.1&deg;W. Find the Sun's declination using the Nautical Almanac. Calculate the true amplitude using the formula sin(Amp) = sin(Dec) / cos(Lat). Comparing the true amplitude to the magnetic bearing of 283.7° and applying the 13.0°E variation yields a deviation of 0.1°W.