On 29 April your 0530 zone time position was LAT 23°04.0'S, LONG 162°12.0'E. Your vessel was steaming on course 120°T at a speed of 9.0 knots. An observation of the Sun's upper limb was made at 0830 ZT. The chronometer read 09h 27m 32s and was slow 02m 24s. The observed altitude (Ho) was 24°58.0'. LAN occurred at 1205 zone time. The observed altitude (Ho) was 52°04.0'. What was the longitude of your 1200 zone time running fix?

Question

On 29 April your 0530 zone time position was LAT 23&deg;04.0'S, LONG 162&deg;12.0'E. Your vessel was steaming on course 120&deg;T at a speed of 9.0 knots. An observation of the Sun's upper limb was made at 0830 ZT. The chronometer read 09h 27m 32s and was slow 02m 24s. The observed altitude (Ho) was 24&deg;58.0'. LAN occurred at 1205 zone time. The observed altitude (Ho) was 52&deg;04.0'. What was the longitude of your 1200 zone time running fix?

Accepted Answer

Option B: LONG 163&deg;06.0'E. Use the running fix method by advancing the 0830 ZT sun line to the 1200 ZT LAN position. Calculate the longitude of the noon sight by comparing the observed time of LAN with the GHA of the Sun at that instant. The resulting longitude is 163°06.0'E.