摘要: A marine lantern was recently introduced with a 300mm Fresnel acrylic plastic lens. Marine signal lanterns of this construction in 155mm and 250mm sizes have previously been photometrically tested and found to be more efficient th... 展开 A marine lantern was recently introduced with a 300mm Fresnel acrylic plastic lens. Marine signal lanterns of this construction in 155mm and 250mm sizes have previously been photometrically tested and found to be more efficient than lanterns using pressed glass Fresnel lenses. A comparison test of all three acrylic plastic lenses is described herein. Photometric characteristics of the lanterns were measured using the same marine signal lamps and six-place lampchanger for all lanterns to afford direct comparison. (Author) 收起