This is demonstration of two views of a spectrum - the "by eye" view through a diffraction grating and a 1D spectrum plot (as from a spectrometer). This also illustrates the color each combination of wavelengths would look to the human eye.

The brightnesses for the emission lines are not based on calculations of gas temperature, density, and radiation field. They are approximations, tuned to approximate what is seen in the particular set of emission lamps currently used by the Foothill College Astronomy Department.

The Doppler shift shows only the shift in emission wavelength, without adjusting the brightness (which in the thermal emission case is reported in W per sq. meter per steradian per meter - divide by 10^12 for the more intuitive kW per sq. meter per steradian per nm).

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