You observe the lower limb of the Sun at a sextant altitude (hs) of 50°26.9' on 9 November. The index error is 1.5' on the arc. The height of eye is 56 feet (17 meters). What is the observed altitude (Ho)?

Correct Answer: Option A — 50°33.5'

Observed altitude calculation starts with sextant altitude, applying index error (subtracted since it is on the arc), dip correction for height of eye, and the Nautical Almanac correction for refraction and semi-diameter.