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This picture shows the difference after the city of Dunedin, New Zealand, changed all its sodium lights to shielded LEDs: https://i.redd.it/hxxp2c3ksdh71.jpg ht

by lanna 5y ago

This picture shows the difference after the city of Dunedin, New Zealand, changed all its sodium lights to shielded LEDs: https://i.redd.it/hxxp2c3ksdh71.jpg https://i.redd.it/hxxp2c3ksdh71.jpg

zaroth 5y ago
The color temperature of sodium lights is so much better at night.
- TeMPOraL 5y ago
  Also sodium lights don't create so many headache-inducing shadow patterns. For example, a street I walked by regularly for almost whole my life recently (in the last few years) got its lighting replaced - each sodium lamp is now replaced with a LED array with no (or ineffective) diffusor. In other words: each spherical source of light got replaced by a bunch of point sources. Last time I walked down that street during night hours, I got a vague feeling as if I was playing an old videogame, because both the road and the sidewalk looked like a low-resolution texture viewed up close: full of smudgy blocks that result from texture upscaling. Except those blocks moved in a weird dance, making my head spin when I focused too much on it, kind of like looking at moving Moiré patterns. Turns out, this was the pattern of shadows thrown by leaves of a tree, when illuminated by half a dozen point light sources. That's my only complaint, though. LED lights are a win overall.
- ericbarrett 5y ago
  San Jose used sodium lamps for years in deference to Lick Observatory, which is on Mt. Hamilton about 15 miles east of the city. The biggest advantage of sodium lights over incandescent for astronomy is that the spectral lines are very distinct and easy enough to filter out when doing scientific studies; incandescent, on the other hand, floods the spectrum broadly up to visible light. I believe LED lamps have similar properties to sodium, although I'm not sure how exact they are compared to sodium lamps—there might be greater variance in the spectra emitted due to material differences; whereas all sodium lamps are arcing through a common atomic element and have very predictable wavelengths.

by lanna 5y ago

This picture shows the difference after the city of Dunedin, New Zealand, changed all its sodium lights to shielded LEDs: https://i.redd.it/hxxp2c3ksdh71.jpg https://i.redd.it/hxxp2c3ksdh71.jpg

zaroth 5y ago

The color temperature of sodium lights is so much better at night.

TeMPOraL 5y ago
Also sodium lights don't create so many headache-inducing shadow patterns. For example, a street I walked by regularly for almost whole my life recently (in the last few years) got its lighting replaced - each sodium lamp is now replaced with a LED array with no (or ineffective) diffusor. In other words: each spherical source of light got replaced by a bunch of point sources. Last time I walked down that street during night hours, I got a vague feeling as if I was playing an old videogame, because both the road and the sidewalk looked like a low-resolution texture viewed up close: full of smudgy blocks that result from texture upscaling. Except those blocks moved in a weird dance, making my head spin when I focused too much on it, kind of like looking at moving Moiré patterns. Turns out, this was the pattern of shadows thrown by leaves of a tree, when illuminated by half a dozen point light sources. That's my only complaint, though. LED lights are a win overall.
ericbarrett 5y ago
San Jose used sodium lamps for years in deference to Lick Observatory, which is on Mt. Hamilton about 15 miles east of the city. The biggest advantage of sodium lights over incandescent for astronomy is that the spectral lines are very distinct and easy enough to filter out when doing scientific studies; incandescent, on the other hand, floods the spectrum broadly up to visible light. I believe LED lamps have similar properties to sodium, although I'm not sure how exact they are compared to sodium lamps—there might be greater variance in the spectra emitted due to material differences; whereas all sodium lamps are arcing through a common atomic element and have very predictable wavelengths.