Celestial Navigation · Circle of Position — Concept
A single sextant altitude of a body places the observer somewhere on a:
- AGreat circle through both poles
- BStraight line of longitude
- CCircle of equal altitude centered on the body's geographical position✓ Correct
- DRhumb line toward the body
Explanation
Every point from which the body shows the same altitude lies on a circle centered on the GP, with radius equal to the zenith distance (90° − Ho). The plotted LOP is a short, essentially straight, portion of this very large circle near the DR.
Authority: Bowditch (Pub. No. 9), Circle of Equal Altitude
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