On 10 August your vessel's 0426 zone time DR position is LAT 52°07'N, LONG 142°16'E, when an amplitude of the Sun is observed. The Sun's lower limb is about 20 minutes of arc above the visible horizon and bears 074.5° per standard compass. Variation in the area is 12°W. The chronometer reads 07h 24m 19s and is 02m 34s fast. Which of the following is the deviation of the standard compass?

Question

On 10 August your vessel's 0426 zone time DR position is LAT 52&deg;07'N, LONG 142&deg;16'E, when an amplitude of the Sun is observed. The Sun's lower limb is about 20 minutes of arc above the visible horizon and bears 074.5&deg; per standard compass. Variation in the area is 12&deg;W. The chronometer reads 07h 24m 19s and is 02m 34s fast. Which of the following is the deviation of the standard compass?

Accepted Answer

Option C: 1.3&deg;E. Calculate the Sun's declination and LHA using the corrected GMT. Determine the True amplitude using sin(Amp) = sin(Dec) / cos(Lat). The difference between the True bearing and the compass bearing (074.5°) provides the compass error. Applying the 12°W variation to this error results in a deviation of 1.3°E.