You observe the lower limb of the Sun at a sextant altitude (hs) of 41°29.8' on 11 January. The index error is 2.4' off the arc. The height of eye is 68 feet. What is the observed altitude (Ho)?

Correct Answer: Option A — 41°39.4'

Applying index error (off the arc, so added), dip correction for a 68-foot height of eye, and the semidiameter and parallax corrections from the Nautical Almanac to the sextant altitude yields the exact observed altitude (Ho) of 41°39.4' per Bowditch celestial reduction methods.