On 16 September your 0600 ZT fix gives you a position of LAT 29°47.2'N, LONG 65°28.4'W. Your vessel is on course 242°T and your speed is 13.5 knots. Local apparent noon (LAN) occurs at 1227 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 63°25.3'. What is the calculated latitude at LAN?

Question

On 16 September your 0600 ZT fix gives you a position of LAT 29&deg;47.2'N, LONG 65&deg;28.4'W. Your vessel is on course 242&deg;T and your speed is 13.5 knots. Local apparent noon (LAN) occurs at 1227 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 63&deg;25.3'. What is the calculated latitude at LAN?

Accepted Answer

Option C: 29&deg;04.7'N. Calculate the Sun's declination at LAN using the Nautical Almanac. Determine the zenith distance (90° - Ho). Since the vessel is in the Northern Hemisphere, Latitude = Declination + Zenith Distance. Applying these values yields 29°04.7'N, consistent with the meridian altitude method for determining latitude at local noon.