On 18 November your 1750 zone time DR position is LONG 110°16.0' W. At that time you observe Polaris with a sextant altitude (hs) of 21°29.8'. The chronometer time of the sight is 00h 52m 43s, and the chronometer error is 02m 18s fast. The index error is 3.2' on the arc, and the height of eye is 49.5 feet. What is your latitude by Polaris?

Question

On 18 November your 1750 zone time DR position is LONG 110&deg;16.0' W. At that time you observe Polaris with a sextant altitude (hs) of 21&deg;29.8'. The chronometer time of the sight is 00h 52m 43s, and the chronometer error is 02m 18s fast. The index error is 3.2' on the arc, and the height of eye is 49.5 feet. What is your latitude by Polaris?

Accepted Answer

Option A: 21&deg;03.4'N. Polaris latitude is derived from true altitude (Ho) minus 1 degree, modified by tabular correction factors $a_0$, $a_1$, and $a_2$ based on local hour angle of Aries, yielding 21°03.4'N.