Celestial Navigation · Sextant Corrections
The observed altitude (Ho) is:
- AThe raw reading taken directly off the sextant arc
- BThe sextant altitude corrected only for index error
- CThe apparent altitude before refraction is applied
- DThe fully corrected altitude, ready to compare against the computed altitude✓ Correct
Explanation
Ho is the sextant altitude after all corrections (index error, dip, refraction, semi-diameter, parallax). It is compared with the computed altitude Hc from sight-reduction tables to find the intercept.
Authority: Bowditch (Pub. No. 9)
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