In the Bay of Fundy, during twilight, you a take sight of Mars. The sextant altitude (hs) is 03°35.5'. Your height of eye is 32 feet and there is no index error. The air temperature is -10°C and the barometer reads 1010 millibars. What is the observed altitude (Ho)?

Correct Answer: Option B — 03°15.8'

Per Bowditch, observed altitude requires applying dip correction for a 32-foot height of eye (-5.6') and refraction correction from the Nautical Almanac tables, adjusted for extreme temperature (-10°C) and pressure (1010 mb), yielding an Ho of 03°15.8'.