[A complimentary Cc of this posting was sent to
HvdV
], who wrote in article :
filtered flow. With constant spectral density at
1 photon/(sec*mkm*m^2), const = h * c, so the eye-corrected energy
flow is 3.82082403851941e-20 W/m^2 = 2.60962281830876e-17 lux.
What unit is 'mkm', wavenumber?

Yes (?); Wavelength. IIRC, wavenumber is 1/wavelength (or some such;
2pi comes to mind...).

[BTW, because of non-linearity of wavelength vs wavenumber, spectral
density which constant per wavelength becomes very non-constant when
measured per wavenumber.]

Yours,
Ilya