On 25 August your 1926 zone time DR position is LAT 24°17.0'S, LONG 05°47.0'W. At that time, you observe Fomalhaut bearing 117°psc. The chronometer reads 07h 26m 52s, and the chronometer error is 00m 15s fast. The variation is 1.5°E. What is the deviation of the standard magnetic compass?

Question

On 25 August your 1926 zone time DR position is LAT 24&deg;17.0'S, LONG 05&deg;47.0'W. At that time, you observe Fomalhaut bearing 117&deg;psc. The chronometer reads 07h 26m 52s, and the chronometer error is 00m 15s fast. The variation is 1.5&deg;E. What is the deviation of the standard magnetic compass?

Accepted Answer

Option D: 2.8&deg;W. Determining compass deviation requires finding Greenwich Mean Time, extracting Local Hour Angle and declination, computing true azimuth of Fomalhaut, converting to magnetic via variation, and comparing against the compass bearing of 117°psc, resulting in 2.8°W deviation.