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)?

Question

You observe the lower limb of the Sun at a sextant altitude (hs) of 41&deg;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)?

Accepted Answer

Option B: 41&deg;39.4'. Applying Bowditch rules, index error 'off the arc' is added to hs. Subtracting dip for a 68-foot height of eye, adding solar semidiameter, and applying refraction yields the precise observed altitude of 41&deg;39.4'.

You observe the lower limb of the Sun at a sextant altitude (hs) of 41&deg;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)?

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)?