On 12 June your 1945 DR position is LAT 21°47.0'N, LONG 46°52.0'W when you observe a faint unidentifiable star through a break in the clouds. The star bears 130°T at a sextant altitude (hs) of 45°21.2'. The index error is 0.5' on the arc, and the height of eye is 45 feet. The chronometer reads 10h 43m 27s, and the chronometer error is 1m 46s slow. What star did you observe?

Question

On 12 June your 1945 DR position is LAT 21&deg;47.0'N, LONG 46&deg;52.0'W when you observe a faint unidentifiable star through a break in the clouds. The star bears 130&deg;T at a sextant altitude (hs) of 45&deg;21.2'. The index error is 0.5' on the arc, and the height of eye is 45 feet. The chronometer reads 10h 43m 27s, and the chronometer error is 1m 46s slow. What star did you observe?

Accepted Answer

Option C: Beta Librae. Determine GHA Aries and the star's sidereal hour angle (SHA) from the Nautical Almanac. Calculate LHA by adding SHA to GHA Aries and subtracting longitude. Compare the resulting LHA and Declination against the star list. Beta Librae aligns with the calculated position and altitude, confirming the star's identity.