Next message: Philip J. Rosch: "RE: T&T: Fl G 4s 16ft 4M "27""
Monday, November 1, 2004, 3:06:15 AM, Jim wrote:
JA> Regarding:
JA> Both the Nominal and Luminous ranges do not take into account elevation,
JA> observer's height of eye, or the curvature of the earth.
JA> ~~~~~~~~~~~~~~~~~~~
JA> It seems to me that you wouldn't mount a 4M light on a 1ft pole. I don't
JA> have the equation for earth's curvature in front of me, but how far away can
JA> a 16ft light be seen from say a helmperson 12ft above the water?
Distance to the horizon (in miles) is 1.17 times the square root of the height of the light or eye (in feet).
Using that equation, the distance from the light to its horizon is about 4.7 miles. For the observer, the distance to the horizon is 4 miles, for a total distance of 8.7 miles.
--
Peter Bennett, VE7CEI Vancouver, B.C., Canada
Lien Hwa 28 (AKA Polaris 30) "Sea Spray"
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
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