Celestial Navigation · Altitude Definitions
Place these altitudes in the correct order of correction from raw reading to final: sextant altitude (hs), apparent altitude (ha), observed altitude (Ho).
- Aha → hs → Ho
- BHo → ha → hs
- Chs → ha (after IC and dip) → Ho (after the main altitude correction)✓ Correct
- Dhs → Ho → ha
Explanation
The sextant reading is hs. Applying index correction and dip yields apparent altitude (ha). Applying the main altitude correction (refraction, and semidiameter/parallax for sun/moon) yields observed altitude (Ho), which is then compared with computed altitude (Hc) in the intercept method.
Authority: Nautical Almanac; Bowditch (Pub. No. 9), altitude corrections
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