What to know for Sextant Use and Corrections
Convert a raw sextant observation into a corrected altitude using the right corrections.
Taking an altitude, index error, dip, refraction, semi-diameter, and observation discipline. This module is mapped to the published course boundary for Yachtmaster Ocean and Astro Navigation Revision and written as an independent revision aid, not official training material.
Key Points
- Measure altitude carefully and record time exactly
- Index error and dip are early corrections
- Refraction and body-specific corrections matter
- Good technique reduces random error
Last reviewed: 6 July 2026 by Compass Revision curriculum review
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