Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 258
e,however, 45° zones may introduce anerror of two or three per cent. Theapparent spherical reduction factor =Q R/O h. Moreover, since the total flux of lightemitted by a virtual point source is 4^times its mean spherical intensity, itfollows that if a circle were drawn withradius Q Q, the length of… … Fig. 1.—New Diagram of Simple Circular Polar Curve depressed diametrically 45°. Rectified by 45° zones.
Lighting
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