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 313°T at a sextant altitude (hs) of 14°56.3'. 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 — Mirzam
Correct the sextant altitude for index error and dip to find Ho. Calculate the LHA and declination for the observation time. Using the sight reduction process, the calculated altitude and azimuth correspond to the star Mirzam, confirming its identity based on the observed bearing.
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