On 25 December you observe the Sun's lower limb. The sextant altitude (hs) is 4°06.9'. The height of eye is 47 feet and the index error is 1.6' on the arc. The temperature is 19°F and the barometer reads 1030.8 millibars. What is the observed altitude (Ho)?
Official USCG Answer & Rule Citation
Correct Answer: Option B — 4°01.9'
Applying index error (-1.6'), dip correction for 47 ft, semi-diameter, and extreme refraction corrections for 19°F and 1030.8 mb from Nautical Almanac tables yields an observed altitude (Ho) of 4°01.9'.
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