On 11 March your 1846 zone time DR position is LAT 25°05.7' N, LONG 124°29.0' W. At that time you observe Polaris with a sextant altitude (hs) of 25°59.1'. The chronometer time of the sight is 02h 44m 01s, and the chronometer error is 02m 15s slow. The index error is 3.9' on the arc, and the height of eye is 42.7 feet (13.0 meters). What is your latitude by Polaris?

Question

On 11 March your 1846 zone time DR position is LAT 25&deg;05.7' N, LONG 124&deg;29.0' W. At that time you observe Polaris with a sextant altitude (hs) of 25&deg;59.1'. The chronometer time of the sight is 02h 44m 01s, and the chronometer error is 02m 15s slow. The index error is 3.9' on the arc, and the height of eye is 42.7 feet (13.0 meters). What is your latitude by Polaris?

Accepted Answer

Option B: 25&deg;17.9'N. Polaris altitude reduction utilizes Bowditch methods. Correct index error (on the arc subtracts), apply height of eye dip correction, and extract SHA and Declination from the Nautical Almanac. Apply local hour angle of Aries to compute precise latitude.