On 16 December your 1810 zone time DR position is LONG 129°46.5' W. At that time you observe Polaris with a sextant altitude (hs) of 23°56.8'. The chronometer time of the sight is 03h 12m 31s, and the chronometer error is 02m 16s fast. The index error is 2.5' off the arc, and the height of eye is 52.6 feet. What is your latitude by Polaris?
Official USCG Answer & Rule Citation
Correct Answer: Option A — 23°07.8'N
Correct the sextant altitude for index error (+2.5') and dip (52.6 ft) to find Ho. Determine LHA Aries using GHA Aries and the DR longitude. Apply the Polaris correction tables (a0, a1, a2) from the Nautical Almanac to Ho to derive the final latitude of 23°07.8'N.
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