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 270°T at a sextant altitude (hs) of 65°41.7'. 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 A — Algeiba
Correct hs for index error (on the arc is subtractive), dip, and refraction to find Ho. Calculate GMT and LHA. Using sight reduction tables, determine the intercept and azimuth. The calculated position and bearing align with Algeiba, confirming the star identification through standard celestial navigation reduction procedures.
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