On 9 February your 0739 zone time DR position is LAT 23°31.0'N, LONG 143°41.0'E. At that time, you observe the Sun bearing 104.5°psc. The chronometer reads 09h 37m 12s, and the chronometer error is 01m 52s slow. The variation is 3.5°W. What is the deviation of the standard magnetic compass?

Question

On 9 February your 0739 zone time DR position is LAT 23&deg;31.0'N, LONG 143&deg;41.0'E. At that time, you observe the Sun bearing 104.5&deg;psc. The chronometer reads 09h 37m 12s, and the chronometer error is 01m 52s slow. The variation is 3.5&deg;W. What is the deviation of the standard magnetic compass?

Accepted Answer

Option D: 8.6&deg;E. Calculate the Sun's declination for 9 February. Determine the true amplitude using sin(Amp) = sin(Dec) / cos(Lat). Convert the true amplitude to a true bearing. Apply the 3.5°W variation to the compass bearing of 104.5°psc to find the magnetic bearing. The difference between true and magnetic bearings results in 8.6°E deviation.