On 7 November your 0830 zone time fix gives you a position of LAT 27°36.0'N, LONG 162°19.0'W. Your vessel is on course 289°T and your speed is 19.0 knots. Local apparent noon (LAN) occurs at 1138 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 45°35.0'. What is the latitude at 1200 ZT?

Question

On 7 November your 0830 zone time fix gives you a position of LAT 27&deg;36.0'N, LONG 162&deg;19.0'W. Your vessel is on course 289&deg;T and your speed is 19.0 knots. Local apparent noon (LAN) occurs at 1138 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 45&deg;35.0'. What is the latitude at 1200 ZT?

Accepted Answer

Option C: 27&deg;59.5'N. Calculate the LAN latitude using the meridian altitude formula. Then, advance this position to 1200 ZT using the vessel's course of 289°T and speed of 19.0 knots. The 22-minute difference between 1138 ZT and 1200 ZT results in a final latitude of 27°59.5'N.