On 16 January, you take a sight of a star. The sextant altitude (hs) is 4°33.0'. The temperature is -10°C, and the barometer reads 992 millibars. The height of eye is 42 feet. The index error is 1.9' off the arc. What is the observed altitude (Ho)?

Question

On 16 January, you take a sight of a star. The sextant altitude (hs) is 4&deg;33.0'. The temperature is -10&deg;C, and the barometer reads 992 millibars. The height of eye is 42 feet. The index error is 1.9' off the arc. What is the observed altitude (Ho)?

Accepted Answer

Option C: 4&deg;17.0'. Applying corrections from the Nautical Almanac and Bowditch: sextant altitude corrected for index error ('on the arc' subtracts), height of eye dip correction, and standard refraction for low altitudes yields the true observed altitude (Ho) of 4°17.0'.

On 16 January, you take a sight of a star. The sextant altitude (hs) is 4&deg;33.0'. The temperature is -10&deg;C, and the barometer reads 992 millibars. The height of eye is 42 feet. The index error is 1.9' off the arc. What is the observed altitude (Ho)?

On 16 January, you take a sight of a star. The sextant altitude (hs) is 4°33.0'. The temperature is -10°C, and the barometer reads 992 millibars. The height of eye is 42 feet. The index error is 1.9' off the arc. What is the observed altitude (Ho)?