You observe the lower limb of the Sun at a sextant altitude (hs) of 31°31.5' on 6 March. The index error is 2.5' on the arc. The height of eye is 76 feet. What is the observed altitude (Ho)?

Question

You observe the lower limb of the Sun at a sextant altitude (hs) of 31&deg;31.5' on 6 March. The index error is 2.5' on the arc. The height of eye is 76 feet. What is the observed altitude (Ho)?

Accepted Answer

Option A: 31&deg;35.3'. Per Bowditch celestial navigation standards, index error 'on the arc' is subtracted from sextant altitude. Subtracting the dip for a 76-foot height of eye and incorporating solar semidiameter and refraction corrections gives an Ho of 31&deg;35.3'.

You observe the lower limb of the Sun at a sextant altitude (hs) of 31&deg;31.5' on 6 March. The index error is 2.5' on the arc. The height of eye is 76 feet. What is the observed altitude (Ho)?

You observe the lower limb of the Sun at a sextant altitude (hs) of 31°31.5' on 6 March. The index error is 2.5' on the arc. The height of eye is 76 feet. What is the observed altitude (Ho)?