On 12 March your 1846 zone time DR position is LONG 129°16.5' W. At that time you observe Polaris with a sextant altitude (hs) of 28°01.5'. The chronometer time of the sight is 03h 44m 10s, and the chronometer error is 01m 55s slow. The index error is 2.2' off the arc, and the height of eye is 59.8 feet (18.2 m). What is your latitude by Polaris?

Question

On 12 March your 1846 zone time DR position is LONG 129&deg;16.5' W. At that time you observe Polaris with a sextant altitude (hs) of 28&deg;01.5'. The chronometer time of the sight is 03h 44m 10s, and the chronometer error is 01m 55s slow. The index error is 2.2' off the arc, and the height of eye is 59.8 feet (18.2 m). What is your latitude by Polaris?

Accepted Answer

Option A: 27&deg;33.7'N. Adjust the sextant altitude for index error, dip, and refraction. Calculate the LHA of Aries using the chronometer time and DR longitude. Apply the Polaris correction factors (a0, a1, a2) from the Nautical Almanac to the altitude to determine the latitude, resulting in 27°33.7'N.