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light pollution filter


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i have just read a report on one of the forums which mentioned a light pollution filter. i live in an area where some lights often come on or off... therefore this may just make it a lot easier for me !!!

does a light pollution filter keep ALL of the viewing attributes, colours and clarity expected in a pitch black area yet filter out all the surrounding lights and therefore you will see as much through the scope as if you were in that area.

if so -which is the best one to get please for my new skywatcher200 ? thankyou so much in advance

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Not really no.

Broadband filters (which are the cheaper of the two main types) look purple in daylight and make everything a bit darker; the sky more so.

Narrowband filters (such as the Orion Ultrablock) look like a mirror in daylight and make everything substantially darker, but nebulae less so, thus making them stand out. If you use narrowband filters for what they were designed for - nebulae - they can reveal unseen detail. On other targets they can exaggerate haze I find.

Both types are useful from time-to-time if you can spare the cash - but neither comes close to the experience of being at a good dark-sky site.

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hmm... i might be tempted to get the narrow band in that case in time....

where to find a much darker site though is the trouble - u cant just set up scope any where lol

Depending where you live you might be able to ask some local farmer if you can access their land to set up your scope.

Might be worth have a look around to see if there are any good sites round you.

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If you have the spare cash you could try an Astronomik filter. I have the Baader filter.... its ok but nowhere near as good as these.

Astronomik -Photographic CCD*Filters-

Made in Germany, so its as good as it gets.

I have an Astronomik OIII filter (visual) in the 2" fitting. It's a really effective and optically fine filter and the best I've used to date (and I've tried quite a lot of other UHC and OIII filters).

Access to dark skies is even better than a good filter though. At the SGL5 Star Party recently my 6" refractor was performing (unfiltered) as well as my 10" newtonian does in my moderately light polluted back garden, on DSO's - I wish I'd taken the 10" as well of course ;)

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does a light pollution filter keep ALL of the viewing attributes, colours and clarity expected in a pitch black area yet filter out all the surrounding lights and therefore you will see as much through the scope as if you were in that area.

That would be magic. A filter "filters", meaning that it cuts out light. In some cases this can improve contrast, but the only kind of filter that will make it look like you're in pitch blackness is a completely opaque one!

If you have streetlights that emit at particular wavelengths (i.e. sodium) then those can be filtered. But if the unwanted light is white then there there is no way of separating out that white light from the white light of stars. A possibility is to look at emission nebulae which are emitting at specific wavelengths and filter out everything except those wavelengths: that's what nebula filters do. These are effective in light-polluted areas, though only on nebulae.

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Actualy the moon tends to look a bit rubbish on a full moon.

- it looks vandalised.

It can be quite nice at very low, whole-moon magnifications, but there's not much to see at high mags.

However, once the terminator (shadow) starts to creep back into view, you'll get to explore long craggy length of craters. Yum yum... Very nice and hugely satisfying.

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I have the cheaper SW LPF and i find it a Godsend. It really does eliminate the skyglow from those pesky streetlights. I'm lucky that i am not in actual visual range of any. I have pointed my scope directly at one and the light from it is reduced to almost nothing (it looks like a white light lamp.....but with no glow around it).

However it doesnt stop light from a security light on the house behind me that has a mind of its own and comes on if and when it chooses. But my skyglow problem area to the south has been dealt with very nicely. In general the problem in all directions has been dealt with.

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