A Method of Calculating the Mean Spherical Candle-Power
Tadao IKEJIRI · JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN · 1959
As the study of the subject, various methods such as Russau Diagram, Russel angle method. etc. are well known.The diagram method is generally used as a standard, and the measuring of the distributed flux of the incandescent lamp, etc. is commonly tried by the use of a bench photometer. In this method. fixing a polnt between the test lamp and the standard one, where the illumination is equal and thus determining the distances, among them, we can calculate the mean spherical candle-power under inverse square law by using a planimeter or other instruments.But in this paper, the author tried to introduce a new method to estimate the mean spherical candle-power. That is, in this method, if the ratio of the above two distances is kθ, the angular relation are a=(1-cosθ)·π/2 (θ is inclination angle from the perpendicular axis), and the point kθ are put on the α line as the polar co-ordinate, the area of envelope of curve, which consists of these points is proportional to the total flux of the light source or the mean spherical candle-power. Moreover, we made the approximate formula and angle transformation table.This method depends only upon the ratio of distances. Moreover, it is superior to the convention one in accuracy but easier to do.