On 11 May your vessel's 1839 ZT position is LAT 17°30'N, LONG 63°55'W, when an amplitude of the Sun's center is observed on the celestial horizon bearing 301° per standard magnetic compass. Variation for this area is 10.5°W. The chronometer reads 10h 37m 10s and is 02m 08s slow. What is the deviation of the compass?

Question

On 11 May your vessel's 1839 ZT position is LAT 17&deg;30'N, LONG 63&deg;55'W, when an amplitude of the Sun's center is observed on the celestial horizon bearing 301&deg; per standard magnetic compass. Variation for this area is 10.5&deg;W. The chronometer reads 10h 37m 10s and is 02m 08s slow. What is the deviation of the compass?

Accepted Answer

Option C: 1.5&deg;W. Calculate the Sun's declination for the observation time. Determine the true amplitude using the formula sin(Amp) = sin(Dec) / cos(Lat). Comparing the true amplitude to the magnetic bearing of 301° and applying the 10.5°W variation results in a deviation of 1.5°W.