On 28 July your 0800 zone time (ZT) fix gives you a position of LAT 25°16.0'N, LONG 71°19.0'W. Your vessel is on course 026°T, and your speed is 17.5 knots. Local apparent noon (LAN) occurs at 1150 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 82°28.7'. What is the latitude at 1200 ZT?

Question

On 28 July your 0800 zone time (ZT) fix gives you a position of LAT 25&deg;16.0'N, LONG 71&deg;19.0'W. Your vessel is on course 026&deg;T, and your speed is 17.5 knots. Local apparent noon (LAN) occurs at 1150 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 82&deg;28.7'. What is the latitude at 1200 ZT?

Accepted Answer

Option B: 26&deg;27.6'N. The latitude at LAN is determined by meridian altitude. To find the latitude at 1200 ZT, apply the vessel's course and speed to the LAN position. Advancing the 1150 ZT position by 10 minutes of travel at 17.5 knots results in a latitude of 26°27.6'N.