Over the curve of the water
Each height has its own distance to the horizon, 1.17 × √(feet) nautical miles. Add the two to get the geographic range.
Skill 8 · Light risingProblem 5006
Height of eye 19 ft: when should the light show?
On a clear night your height of eye is 19 ft. You are closing a light listed as 145 ft high, nominal range 9 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
| Height of eye | 19 ft |
|---|---|
| Height of the light | 145 ft |
| Nominal range | 9 nm |
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