Light Pollution filter

[Asur84]

I'm searching for new equipment at th minute and came across a LP filter and was wondering if these are any good at all. It looks identical to the moon filter I already have but if anyone has any experience with these I would appreciate the reviews.

Many thanks.

[Bizibilder]

It all depends on the source of your own light pollution. Many filters work by blocking the yellow of sodium streetlights. Reputable dealers will often let you trial a filter (if you ask them nicely! and will allow you to exchange if unsuitable). Buying one on spec (eg Fleabay) may or may not work with no return if it doesn't.

[Asur84]

If I understand correctly then (a high possibility of being wrong entered here) could colour filters be used in place of LP filters.

[Bizibilder]

In theory, yes. The problem is that coloured filters only let a particular colour through the filter eg red lets through the red part of the spectrum and blocks everything else. A LP filter lets through almost all of the colours of the spectrum except the one(s) causing the pollution eg the standard LP filter for sodium yellow lights blocks only the yellow and lets everything else through.

Narrowband filters are a different animal altogether as these let through quite specific wavelengths (or a very narrow band of wavelengths) of light. These are generally used only for imaging.