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:
“Not every light is a true light;
To the wise the light of truth is light itself.”
—Tiruvalluvar (c. 5th century A.D.)
“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)