You'll forgive me for presenting an answer that's relevant specifically to photography.
Originally Posted by Lee L
This is after all a photography forum, not one for astronomers or physicists.
Since you appear to be well-versed in the theory, you should know that the "color temperature" of any visible black-body spectrum can be calculated by comparing the amplitudes at any two points on the curve. Accuracy is enhanced by choosing two points that are as far apart as possible in wavelength (i.e. color).
It's convenient and less expensive from a manufacturing standpoint to measure red and blue components and compare them. This DOES NOT include green, which is measured separately if at all.
We're dealing with visible light here, with CT in the range roughly 2500° to 6500° k.
Photographers don't care about UV.