Celestial Navigation · Star Selection
For the best fix from a round of star sights, the stars should ideally be:
- AAs low to the horizon as possible to reduce refraction error
- BAll on the same bearing for easy plotting
- CBright, of moderate altitude (about 15°–65°), and spread roughly evenly in azimuth (e.g., three stars ~120° apart)✓ Correct
- DAll near the zenith
Explanation
Good geometry means LOPs crossing near right angles, so bodies spread ~120° apart in azimuth give a strong fix. Moderate altitudes avoid large refraction (too low) and difficult sextant handling (too high); bright stars are easier to observe accurately.
Authority: Bowditch (Pub. No. 9), selecting bodies for observation
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