You are heading south to Puerto Rico and you want to check your latitude as you approach the coast. It is Jan. 12, 2002, (almanac data for 2002 available at www.thenauticalalmanac.com) and your DR position is 18° 15’ N, 68° 14’ W. Precalculate the time of meridian passage in GMT at your DR position.
You observe the sun’s lower limb at meridian passage to determine your latitude. Your height of eye is 12 feet and your sextant has no index error. You shoot the sun at its highest altitude at about 1640 GMT and record an Hs of 49° 55.6’. What is your latitude?
Meridian passage: 1641 GMT
Latitude: 18° 16.8’ N