TABLE 56.— BLACKBODY SPECTRAL INTENSITIES 85 



Auxiliary table for a short method of calculating A for any temperature. (Menzel, Harvard Uni- 

 versity.) 



Let /o = intensity for To = 10,000 °K; for another temperature T °K: 



///.= [X„ 8 (exp (c/KTS - l)]/[X B (exp (c*/\T) — 1)] 



For ease of calculation To was taken as 10,000 °K. A = tabular A X 10" watts, for cm 2 for 2ir solid 

 angle per 0.1m- Choose X = X>To/T ; then A = A( T/ToY. As an example find A for 0.5/* and 6000 °K 

 from value of A for 0.3m given in Table 55. 0.5m =0.3/* 10,000/6000. A for 0.3m = 1.2857 X 10*. A 

 for X = 0.5m = 1.2857 X 10 4 X (6,000/10,000) s = 9.998 X 10 2 . 



SMITHSONIAN PHYSICAL TABLES 



