The Control of Light by a Lighthouse Lens

Publisher Website
Google Scholar
Abstract
The conditions to be fulfilled by a lighthouse lens are briefly described and a short historical survey is made. Elementary theoretical requirements are discussed, with particular reference to the aberrations inherent in the use of glass lenses. Particulars are given of the various approximations which are necessary to make manufacture practicable and the methods used for calculating the axial intensity are described. Recent work on the factors controlling the conspicuity of such lights is discussed, including the Blondel-Rey correction for duration of flash. Methods for computing the range of a beam under various conditions are given, and the range is related to the Standard Visibility Code of the meteorological services. The practical application of these various features to typical lighthouses is described.

This publication has 0 references indexed in Scilit: