On 13 October your 0515 zone time (ZT) fix gives you a position of LAT 26°53.0'N, LONG 90°05.0'W. Your vessel is on course 068°T, and your speed is 7.8 knots. Local apparent noon (LAN) occurs at 1145 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 54°51.5'. What is the calculated latitude at LAN?

Question

Accepted Answer

Option A: 27°12.6'N. Calculate latitude at LAN using the formula L = (90° - Ho) ± Dec. For 13 October, the Sun's declination is approximately 7°48.3'S. Applying the meridian altitude formula: 90° - 54°51.5' = 35°08.5' (Zenith Distance). Adding the South declination yields 27°12.6'N, matching the observed meridian altitude result.