$$
    B_{\lambda}(T)  =  { { { { 2 h c^2 } / { {\lambda}^5 } } } \over 
                        { e^{ {h c} / { \lambda k T } }  - 1 } }
$$

Integrated energy per second over a wavelength range
$$
    {\rm W/m^2}  =  (\pi) \thinspace \int^{\lambda_1}_{\lambda_2}
                        {  { { { { 2 h c^2 } / { {\lambda}^5 } } } \over 
                           { e^{ {h c} / { \lambda k T } }  - 1 } } d\lambda }
$$



\vfill
\eject
\end

