On 21 February your 0823 zone time DR position is LAT 21°44.0'S, LONG 80°14.0'E. At that time, you observe the Sun bearing 096°psc. The chronometer reads 03h 25m 19s, and the chronometer error is 01m 52s fast. The variation is 5°W. What is the deviation of the standard magnetic compass?

Question

On 21 February your 0823 zone time DR position is LAT 21&deg;44.0'S, LONG 80&deg;14.0'E. At that time, you observe the Sun bearing 096&deg;psc. The chronometer reads 03h 25m 19s, and the chronometer error is 01m 52s fast. The variation is 5&deg;W. What is the deviation of the standard magnetic compass?

Accepted Answer

Option B: 4.7&deg;W. Calculate the Sun's true azimuth using the LHA and declination. Compare the true azimuth to the compass bearing (096°psc) corrected for variation (5°W). The remaining difference is the deviation. Solving the equation True = Compass + Variation + Deviation results in a deviation of 4.7°W.