Data of a glass filter combination converting the spectral responsivit
y of the GaP photoelement to the window-function cutting off the UV-A
band and a probe structure realizing the cosine character directional
response are given. Systems for measuring the spectral characteristics
of the photoelement and the filters, and for measuring the directiona
l characteristic of the probe, as well as the software that optimizes
the thicknesses of the filters for reaching the minimal integral error
are touched on.