Help needed for Photographic filters

[Astroman]

Hi Guys,

I am trying to work out the best filter to use for Photography under light polluted skies. The biggest problem I have are the sodium lights which give off an orange glow. This seems to be the main problem I have. I am trying to reduce the effects of the pollution and need a filter to do it. Can someone recommend a good 2" filter that would work well in this situation?

[acropolite]

There are some filters listed here (http://www.sciencecenter.net/hutech/canon.htm) for light pollution, how effective they are for Sodium vapour, I'm not sure and they're not cheap.

[Solanum]

You need to know the emission spectrum of the street lights. Low pressure sodium lighting is dominated (but is not exclusively) by sodium lines, something like 590nm I think. Then you need a filter that blocks that part of the spectrum. However, you'd want to check that the 590nm part of the spectrum isn't important for your photographic objects.