On 12 September your 0600 zone time (ZT) fix gives you a position of LAT 22°51.9'N, LONG 133°40.1'W. Your vessel is on course 062°T, and your speed is 12.3 knots. Local apparent noon (LAN) occurs at 1142 ZT, at which time a meridian altitude of the Sun's upper limb is observed. The observed altitude (Ho) for this sight is 70°33.2'. What is the calculated latitude at LAN?

Question

On 12 September your 0600 zone time (ZT) fix gives you a position of LAT 22&deg;51.9'N, LONG 133&deg;40.1'W. Your vessel is on course 062&deg;T, and your speed is 12.3 knots. Local apparent noon (LAN) occurs at 1142 ZT, at which time a meridian altitude of the Sun's upper limb is observed. The observed altitude (Ho) for this sight is 70&deg;33.2'. What is the calculated latitude at LAN?

Accepted Answer

Option B: 23&deg;24.8'N. Calculate the latitude at LAN using the meridian altitude formula: Lat = (90° - Ho) ± Dec. Ensure the upper limb correction is applied to the Ho. Using the Sun's declination for the time of LAN, the resulting latitude is 23°24.8'N.