On 7 December your vessel's 0835 zone time DR position is LAT 28°30.0'N, LONG 125°39.3'W, when an azimuth of the Sun is observed. The chronometer time of the sight is 04h 34m 48s, and the Sun is bearing 113° per standard magnetic compass. The chronometer error is 01m 24s slow, and the variation in the area is 13.0°E. What is the deviation of the standard magnetic compass?

Question

On 7 December your vessel's 0835 zone time DR position is LAT 28&deg;30.0'N, LONG 125&deg;39.3'W, when an azimuth of the Sun is observed. The chronometer time of the sight is 04h 34m 48s, and the Sun is bearing 113&deg; per standard magnetic compass. The chronometer error is 01m 24s slow, and the variation in the area is 13.0&deg;E. What is the deviation of the standard magnetic compass?

Accepted Answer

Option C: 2.3&deg;E. Calculate the Greenwich Mean Time (GMT) to determine the Sun's true azimuth via the Nautical Almanac. Applying the formula Compass Error = Variation + Deviation, the difference between the true azimuth and the compass bearing, adjusted for 13.0°E variation, confirms a deviation of 2.3°E for the standard magnetic compass.