Navigation General · Light Ranges
The geographic range at which a light may be seen depends primarily on:
- AThe candlepower of the light
- BThe phase of the moon
- CThe color of the light
- DThe height of the light and the height of the observer's eye (their combined distances to the horizon)✓ Correct
Explanation
Geographic range is limited by the curvature of the Earth: it is the sum of the distance to the horizon from the light's height and from the observer's height. A powerful light can still be hidden below the horizon if it or the observer is low.
Authority: USCG Light List; Bowditch (Pub. 9)
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