On the temperature dependence of the lower wavelength cutoff of a series of Schott glass filters

The authors have extended the work of Ångström & Drummond concerning the temperature dependence of the three meteorological standard filters (Schott OG 1, RG2 and RG8) and here give values of the temperature coefficient of the center of lower cutoff for seven other Schott sharp cutoff filters. The results demonstrate that there is a definite relationship between the normalized cutoff wavelength and this coefficient, the coefficient increasing semi-logarithmically with wavelength over the region 440–920 millimicrons.