Light Pollution Considerations
For placements where light pollution is of prime importance (for example, an observatory parking lot), low pressure sodium is preferred. As it emits light on only one wavelength, it is the easiest to filter out. Mercury vapor lamps without any phosphor are second best; they produce only a few distinct mercury lines that need to be filtered out.
Read more about this topic: Mercury-vapor Lamp
Famous quotes containing the words light and/or pollution:
“for beauty with sorrow
Is a burden hard to be borne:
The evening light on the foam, and the swans, there;
That music, remote, forlorn.”
—Walter De La Mare (1873–1956)
“Like the effects of industrial pollution ... the AIDS crisis is evidence of a world in which nothing important is regional, local, limited; in which everything that can circulate does, and every problem is, or is destined to become, worldwide.”
—Susan Sontag (b. 1933)