The Characteristics of a Photo-Electric Baffle Tube Type Brightness Meter

The characteristics of a brightness meter having a baffle tube, i.e., directional sensitivity and scanning field angle, have been investigated theoretically and experimentally. Especially, the design of the baffle tube has been treated theoretically and the characteristics of the directional sensitivity, compared with the experimental results. The relation between the source size and the aperture scanning anglel of the instrument has been considered with the directional sensitivity and also the accuracy of this instrument has been discussed.