On 15 November your 0813 zone time (ZT) fix gives you a position of LAT 22°30.0'N, LONG 67°28.0'W. Your vessel is on course 164°T, and your speed is 13.5 knots. Local apparent noon (LAN) occurs at 1215 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 49°46.0'. What is the latitude at 1200 ZT?

Question

On 15 November your 0813 zone time (ZT) fix gives you a position of LAT 22&deg;30.0'N, LONG 67&deg;28.0'W. Your vessel is on course 164&deg;T, and your speed is 13.5 knots. Local apparent noon (LAN) occurs at 1215 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 49&deg;46.0'. What is the latitude at 1200 ZT?

Accepted Answer

Option A: 21&deg;42.5'N. Calculate the latitude at LAN using the meridian altitude formula: Lat = (90° - Ho) ± Dec. Once the 1215 ZT latitude is found, apply the vessel's course and speed to back-calculate the position to 1200 ZT, resulting in a latitude of 21°42.5'N.