On 23 May your 0628 zone time position was LAT 28°18.0'S, LONG 102°42.0'E. Your vessel was steaming on course 040°T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 0758 ZT. The chronometer read 01h 02m 06s and was fast 04m 04s. The observed altitude (Ho) was 13°16.7'. LAN occurred at 1201 zone time. The observed altitude (Ho) was 42°32.0'. What was the longitude of your 1201 zone time running fix?

Question

On 23 May your 0628 zone time position was LAT 28&deg;18.0'S, LONG 102&deg;42.0'E. Your vessel was steaming on course 040&deg;T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 0758 ZT. The chronometer read 01h 02m 06s and was fast 04m 04s. The observed altitude (Ho) was 13&deg;16.7'. LAN occurred at 1201 zone time. The observed altitude (Ho) was 42&deg;32.0'. What was the longitude of your 1201 zone time running fix?

Accepted Answer

Option C: 104&deg;03.5'E. Calculate the latitude at LAN using the meridian altitude formula. Advance the 0758 ZT sun line to the 1201 ZT LAN position using the vessel's course and speed. The intersection of the advanced sun line and the meridian latitude provides the longitude of the running fix at 104°03.5'E.