On 12 June your 1845 DR position is LAT 21°47'N, LONG 46°52'W when you observe a faint unidentifiable star through a break in the clouds. The star bears 162°T at a sextant altitude (hs) of 28°36.5'. The index error is 0.5'on the arc, and the height of eye is 45 feet. The chronometer reads 09h 43m 27s, and the chronometer error is 1m 46s slow. What star did you observe?
Official USCG Answer & Rule Citation
Correct Answer: Option D — Iota Centauri
Correct the sextant altitude for index error, dip, and refraction to obtain Ho. Calculate UTC, GHA Aries, and SHA. Compute LHA and Declination. The resulting coordinates match Iota Centauri, confirming the star identification through standard celestial navigation reduction procedures as required by USCG examination standards.
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