SPECPR Users’ Manual                                                   Page 8-f6.1

F6:  Black Body Computation                               Alias: plan[ck]
This function computes the Planck black body function
at a given temperature (in degrees Kelvin) and any
wavelength set.  Currently, the output is in watts per square meter
per micron per steradian and the input wavelength set is assumed to
be in microns.
Upon entering the routine, you are asked to type
in the temperature and the wavelength id and record number.  When using extreme
temperatures or extreme wavelengths, you should check the results
for underflow or overflow in the CRT plot routines (Chapter 9).
No file or errors are needed since this routine generates a new
file instead of an operation on an old one.  The equation used is

HTML-IMAGEcpile { E sub i (T) ={ 8 pi h c sup 2 } over { lambda sup 5 }
left [ e sup {{ h
c}  over { lambda k T }} - 1 right ] sup -1
        ={ 1.4966 times 10 sup -5 } over lambda sup -5 left [ e sup
{13586 over { lambda T } } -1 right ] sup -1 }
where E is the energy for each channel at wavelength,
      λ (in microns),
      T is the temperature (degrees Kelvin),
      c is the speed of light,
      h is the Planck constant (= 6.6252×10-34 Joule-seconds),

 and k is the Boltzmann constant (= 1.3806×10-23 Joule/°K).