alt Hacker News> that's why they were the color they were
That doesn't seem right to me. Sodium (and mercury) vapor lamps are the color they are due to physics, and were chosen because they're very efficient (and long lasting). Low-pressure sodium is the best and worst of these; essentially monochromatic but fantastic efficiency. Their only advantage, color-wise, is that the light can be filtered out easily (they used to be widely used in San Jose because Lick Observatory could filter out the 589 nm light).
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...And the old Engineer was just saying that that was the area on the spectrum they aimed for, so they found a light that emitted in that wavelength that could be technically implemented and scaled.
Way better work than whoever it is handling this LED nonsense. Why we can't find a diode that we can use to simulate the old spectra would be a fun research project.
The monochromatic light emitted from sodium lamps is also close to the peak sensitivity of the human eye. Colours are not distinguishable, but contrast is much enhanced compared to “cooler” light sources.
*edit: but it’s the overwhelmingly larger lifespan (20-30k hrs) that led to the wide adoption as streetlights. And I guess, the same is true for the change to led today, because of less power consumption.