Industrial Purpose

[RastaKaze]

I was just wondering, why the fuck were high pressure sodium lamps created, and when. and what's the COMMERCIAL use for them??

[sharpezor]

good question, i dont know,

probably for greenhouse farmers or something :confused:

[Zandor]

Warehouse or outdoor lighting first comes to mind. In large stores they are hanging from the roof and have round glass reflectors directing light to the ground. Streetlights are Mh and HPS depending on the weather. In fog conditions HPS light will penetrate and MH will not. Those are a few of the uses of them and why there are so many around. They were not invented for growing we just got lucky.

[stickygreenlightsabr]

To add to the information Zandor gave...

HPS lights, because they are redder than MH, have longer wavelengths. The MH light travels poorly in fog because the blue light, with its shorter wavelength, easily bumps into particles in the fog and then gets absorbed and scattered. You can think of the longer red wavelength of the HPS as being able to curve over the particles better.

This is also why the sunset and the lunar eclipses appear reddish. Most of the suns light gets scattered while the longer redder wavelengths are able to penetrate the Earths atmosphere.