On 23 June in DR position LAT 21°39.0'S, LONG 106°28.0'W, you observe an amplitude of the Sun. The Sun's center is on the celestial horizon and bears 078°psc. The chronometer reads 02h 14m 39s and is 01m 43s slow. Variation in the area is 9°W. What is the deviation of the standard magnetic compass?

Question

On 23 June in DR position LAT 21&deg;39.0'S, LONG 106&deg;28.0'W, you observe an amplitude of the Sun. The Sun's center is on the celestial horizon and bears 078&deg;psc. The chronometer reads 02h 14m 39s and is 01m 43s slow. Variation in the area is 9&deg;W. What is the deviation of the standard magnetic compass?

Accepted Answer

Option C: 4.3&deg;W. Determine the Sun's declination at the time of observation using the Nautical Almanac. Calculate the amplitude using sin(Amp) = sin(Dec) / cos(Lat). Convert the true amplitude to a true bearing. With a variation of 9°W, compare the true bearing to the compass bearing of 078°psc to find 4.3°W deviation.