You observe the lower limb of the Sun at a sextant altitude (hs) of 24°00.7' on 10 January. The index error is 2.6' off the arc. The height of eye is 55 feet. What is the observed altitude (Ho)?

Correct Answer: Option A — 24°10.2'

Apply index error (off = subtract) to the sextant altitude. Subtract the dip correction for a 55-foot height of eye. Apply the Sun's altitude correction (including semi-diameter and parallax) from the Nautical Almanac. The resulting observed altitude (Ho) is 24°10.2', following standard celestial navigation reduction procedures.