Thanks, I fixed the article.

]]>Here are the two graphs of spectral intensity, one plotted vs wavelength and one plotted vs wavenumber:

These were created from the fundamental equations.

Pekka’s explanation is correct.

The way to think about it is, what is **spectral intensity**?

It is how much energy is available between each 1 μm (wavelength);

At least that is the case for the first graph.

But in the second graph it is how much energy is available between each 1 cm^{-1} (wavenumber).

Between 4-5 μm there are 500 cm^{-1} (10000/4 – 10000/5)

Between 29-30 μm there are 11.5 cm^{-1} (10000/29 – 10000/30)

If there is a strongly changing amount of wavenumbers for each wavelength then the peak of one function will be different from the peak of another function.

Does this make sense?

]]>That the curves do actually fit together is the point I have tried to explain. I haven’t used any equations as I that might not be useful. If you could gain understanding from the equations you would probably already understand the point.

]]>I think the curves have the right shape related to each other. And the scales up and down given in wavelenght and wavenumer seem to fit each other. But the scales does not seem to fit the curves. A black body curve for a temperature of 288 Kelvin has it’s peak very near to 10 microns (or 1000 wavelengths/cm). That does not match what you see here taken from Grant Pettys book. ]]>

You are correct, there appears to be something wrong with these graphs. I will look into it and then make further comment.

]]>