Light Pollution

[Madhatter]

Originally Posted by Neil

Metal Halide provide a nice white light and are efficent. They are a discharge type light so take a few minutes to warm up. They can usually be used on SON gear so can be used as a direct replacement. Many of the new street light fitted around us are now white and I suspect they are using metal halide lamps. Only problem for home use is they are quite expensive compared to a £5 150w B&Q halogen light fitting with PIR.

You are of course correct, and I was thinking that going up the motorway to the meet. they don't put sodium lights on the motorway do they, they're mercury vapour, the golden ones, and the crisp white which are appearing more often now, as i assume costs are falling, are metal halide.

[Neil]

Mercury vapour are also white. I think they are very similar to the newer metal halide ones. I think the old orange street lights were a very efficent type of low pressure sodium but not nice to look at. The modern high pressure sodium (HPS) lamps are more yellow and are often used as motorway lights. You can also use high pressure sodium lamps for growing plants as in this example I found on the net

[Madhatter]

lol you naughty naughty boy stealing pictures of marajuwana

[Neil]

OMG is that what it is?