Created on Mon Nov 13 21:58:47 2017.

@author: erwan

Formula to calculate most spectral quantities

Are stored here all equations that need to be used by both the factory (to generate the spectrum) or the spectrum class (to recompute some quantities in post processing)

Derive radiance ($$mW/cm^2/sr/nm$$) from the emissivity.
$I(\lambda) = \epsilon(\lambda) \cdot L_0(\lambda, T)$
radiance – unless unit is different
array in $$mW/sr/cm2/nm$$