Worksheet 405 · Skill 8
Light rising
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On a clear night your height of eye is 24 ft. You are closing a light listed as 85 ft high, nominal range 5 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 12 ft. You are closing a light listed as 105 ft high, nominal range 7 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 22 ft. You are closing a light listed as 45 ft high, nominal range 18 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 25 ft. You are closing a light listed as 100 ft high, nominal range 19 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 16 ft. You are closing a light listed as 35 ft high, nominal range 17 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 12 ft. You are closing a light listed as 155 ft high, nominal range 15 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 14 ft. You are closing a light listed as 160 ft high, nominal range 19 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.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 24 ft. You are closing a light listed as 45 ft high, nominal range 13 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.
Geographic range: ________ nm First seen at: ________ nm
Answer key
| No. | Answers | Problem |
|---|---|---|
| 1 | Geographic range: 16.5 nm First seen at: 5.0 nm | No. 405001 (worked solution) |
| 2 | Geographic range: 16.0 nm First seen at: 7.0 nm | No. 405002 (worked solution) |
| 3 | Geographic range: 13.3 nm First seen at: 13.3 nm | No. 405003 (worked solution) |
| 4 | Geographic range: 17.6 nm First seen at: 17.6 nm | No. 405004 (worked solution) |
| 5 | Geographic range: 11.6 nm First seen at: 11.6 nm | No. 405005 (worked solution) |
| 6 | Geographic range: 18.6 nm First seen at: 15.0 nm | No. 405006 (worked solution) |
| 7 | Geographic range: 19.2 nm First seen at: 19.0 nm | No. 405007 (worked solution) |
| 8 | Geographic range: 13.6 nm First seen at: 13.0 nm | No. 405008 (worked solution) |