Contents
%%% moon.m computes detected signal in a pixel of moon image % by Chuck DiMarzio % Northeastern University % June 2009 %
Compute spectral radiant exitance and spectral photon exitance at 5000K
bbd.m returns spectral data.
[wavelr,mrlambda,wavelv,mvlambda,wavelp,mplambda,m,mv,mp,X,Y,Z]=... bbd(5000,0.35,10); close all; % Close figures generated by bbd fig1=figure;plot(wavelr,mrlambda/m,wavelr,mplambda/mp); xlabel('\lambda, Wavelength, \mu m'); ylabel('f_\lambda, \mu m'); moose=axis;axis([moose(1),3,moose(3:4)]); grid on;
--------- Temperature = 5000 Kelvin Wavelengths from 0.35 to 10 micrometer Peak Spectral Radiant Exitance, m_\lambda = 4.026e+07 Watts/m^2/micron at \lambda = 0.58 microns Radiant Exitance, M = 3.433e+07 Watts/m^2 = 0.9678 of total in 0 to 100 microns --------- Luminous Exitance, Mv = 2.888e+09 l/m^2 Chromaticity, x = 0.34508 y = 0.35161 z = 0.30331 Luminous Efficiency, 84.12 lumens/W --------- Photon Exitance, Mp =1.855e+26 Photons/sec/m^2 Photon Efficiency, 5.402e+18 Photons/sec/W 6.422e+16 Photons/sec/lumen

Compute Conversion factor photons per joule
opticalpower=3.8e-12;
photons_per_joule=mp/m
test=wavelp<0.750; % Cutoff filter: count just the ones in band
fraction_in_band=sum(mplambda(test))/sum(mplambda)
photons_per_second=photons_per_joule*opticalpower*fraction_in_band
photons=photons_per_second/30
photons_per_joule = 5.4023e+18 fraction_in_band = 0.2152 photons_per_second = 4.4180e+06 photons = 1.4727e+05