|
Carlos,
Incandescent is white light generally.
Mercury vapour SHOULD be relatively white, but can appear yellow thanks to the plastic coverings they put over the glass bulbs and housings rapidly discolouring due to the UV emitted by them (compounded with solar UV)
Sodium vapour will look yellow to yellow orange (depending on if high or low pressure units).
I THOUGHT our street lights along the main road (right i my picture) were Sodium vapour, but an Energex guy told me they were Mercury vapour ones in need of replacement.
Sodium vapour is the best for we astronomers, as Na lights emit one line that is easy to remove/filter. Apparently most US cities/towns that have observatories use Na vapour lamps for this very reason.
|