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What light pollution filter?

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Can anybody recommend a good, budget light pollution filter?

I have a Skymax 127 scope - which takes 1.25" eyepieces. By the looks of it - LP filters fit onto the eyepiece (not 100% certain).

Unfortunately I live in quite a bad area for light pollution, but wondered if filters would help me to view nebula or possibly galaxies etc...

Thanks for any tips.

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A UHC filter (e.g. Lumicon) will help you to see emission nebulas (such as Orion nebula etc). I use one and it's great - I don't know what cheaper ones are like.

I noticed a review of "light pollution filters" in this month's Sky At Night mag which is actually a round-up of nebula filters: this might be worth looking at.

All filters work, of course, by blocking light, and can only be effective against light pollution if there are particular wavelengths you want to see (such as oxygen emission lines). Emission nebulas emit light at these special wavelengths, while other objects (stars, galaxies, streetlights) emit a broad spectrum that is effectively white.

Old orange street lights emit at the particular wavelengths of sodium, and if you're lucky enough to live in an area serviced only by these then you can filter them out. But the more modern lights (including ones that look orange but are a lot brighter) can't be filtered out from starlight. So if you want to look at deep sky objects from a light-polluted site then get a nebula filter (OIII, UHC etc) and look for emission nebulas, of which there are many. I've had lovely views of the Dumbell, for example, from my light-washed back garden.

To improve your chances even further, put a hood over your head at the eyepiece so that you can't see any stray light.

Hope this helps.


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I've found that the Baader UHC-S filter works well with smaller aperture scopes (ie: less than 8 inches). It's bandpass is a little wider than a true narrowband but that helps with smaller scopes.


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The only light pollution filter I own at the moment is the Baader Moon and Skyglow. It certainly works in the smaller optics. BIG difference on low pressure Sodium street lights and skyglow.

I am also looking at the Skywatcher OIII and the UHC in the future.


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