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Light pollution filters

Barto

By Barto
in Discussions - Eyepieces

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Pig

Pig

Posted
Posted

I use a 1.25 narrow band UHC filter. However, it works much better in my 9.25" scope than it worked on my 6" scope. I think all the UHC are for sodium light as apposed to LED light :smiley:

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hoops86

hoops86

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I have brutal light pollution in my garden…around 10 sodium lights within 50 yards of me and my only unobstructed view is directly looking at Glasgow…so its pretty much just orange skies.

I have a “moon & skyglow” cheap filter I got for around a tenner. I didn’t like it at all….so I bought the Baader Neodymium filter that Robin mentions above. In my inexperienced opinion…they both suck! Both make my views worse! Maybe they work better for different objects I don’t know. But for me…looking at M13, M92 and M57 all gave me worse views than without a filter. Maybe im doing something wrong :)

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Barto

Barto

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I have brutal light pollution in my garden…around 10 sodium lights within 50 yards of me and my only unobstructed view is directly looking at Glasgow…so its pretty much just orange skies.

I have a “moon & skyglow” cheap filter I got for around a tenner. I didn’t like it at all….so I bought the Baader Neodymium filter that Robin mentions above. In my inexperienced opinion…they both suck! Both make my views worse! Maybe they work better for different objects I don’t know. But for me…looking at M13, M92 and M57 all gave me worse views than without a filter. Maybe im doing something wrong :)

i hope you get posts that can sort this out hoops86 

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laowho

laowho

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In our limited experience there hasn't been anything to help with light pollution other than a screen for our nearby street light, a shroud and dew shield, a higher power low power EP (to darken the sky), and the odd trip to darker skies. Otherwise, the various filters dimmed the stars, but neither have we tried the abovementioned Neodymium.

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Reeny

Reeny

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I have a 32mm moon filter for the small scope.

It's pretty weak at blocking the moon's glare, but raises the contrast up a little.

When the 200p Dob arrives, I will be investing in a 2" UHC filter for viewing nebulas.

I was wondering - will the UHC work OK as a moon filter.

I assume that any filter which can block part of the light spectrum will work to a certain extent.

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laowho

laowho

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Hmmm...

Never tried our UHC on the moon. Seems it would turn it blue the way it does our stars when using it (Orion Ultrablock) on nebulae. For the moon we use a 13% filter sometimes, but only at low-medium powers. More often though, we keep the garage door open so that the light dims the view of the moon. (We also got the Edmund 28mm RKEs on a lark and because of all the hype, and they are far and away our best lunar EPs--they dim it just enough to boost contrast while giving that "floaty" effect.)

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hoops86

hoops86

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I posted a couple of days ago about how i didnt like the baader neodymium filter. I may have been unfair! Ive had 2 good nights of use since then and i actually did notice a decent difference! I think i was expecting too much from it before :)

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Barto

Barto

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I don't bother with LP filters, they don't seem to work very well for visual. Photographically is a different matter however, there they definitely make a big difference.

Thanks for that hoops. Interesting

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  • 3 weeks later...
Stu

Stu

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Apologies if this is stating the obvious, but probably worth mentioning. Any of the filters reduces the light coming through the ep, both the light you want, and the light pollution. This means that getting your eyes dark adapted remains as important when using a filter as when not or the views won't be any better, possibly worse. It's well worth making the effort to screen off lights which you can see directly from where you are observing as these will kill your night vision whenever you look towards them.

Regarding filters, the Neodymium works well, and is also good on Jupiter and Mars. I have a SkyGlow filter which specifically targets sodium lights, worth seeking one if that is the sort of LP you are facing. UHC-S, UHC and OIII are increasing in order of aggressiveness of filtering and thus dimming of the image. Nine will help with galaxies but should assist with nebulae such as M27 and M57. Worth giving a UHC a go maybe, OIII is good for objects like the Veil generally recommended for scopes over 8" but I find it useful still in my 4"

Stu

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rl

rl

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BigMaksutov speaks some sense....

The clue is largely in the name....nebula filters work best on emission nebulae where all the light is at one specific wavelength (colour). They do sod all for galaxies and the moon. In my experience they provide the best improvement from sites that are already not bad...they can turn a good view (of the veil, M42, M1....emission objects) into a brilliant one. They don't seem to be as impressive in really bad light polluted areas where they are most needed..

They are more effective in bigger telescopes.....a filter that's useless in a 4" can do a decent job in a 12" .

To specifics...the lumicon deep sky filter and neodymium filters provide a gentle contrast improvement without losing too many background stars. Narrower bandwidth filters like the Lumicon UHC can give a quite dramatic contrast improvement but you lose a lot of the background stars and the remaining ones all look teal blue. It's a matter of taste.

Not all UHC filters pass the red Hydrogen alpha line..a lot of people reckon you can't see it (only useful for photography) but I disagree...the outer areas of M42 ca be seen as dark chocolate brown using a Lumicon UHC with a 12" from my location. Those filters that do pass the H-alpha line help you to spot red giants easily...the double cluster is a good example.

Nebula filters can show up defects in cheaper eyepieces at the edge of the field...CA will produce closely spaced red and blue star images which can be annoying.

I keep a cheap neodymium fiulter in my 80mm finder...it helps with finding planetry nebulae without dimming everything else excessivley..

Recommended for visual use...Astronomik UHC, Lumicon UHC, Deep-sky, Orion ultrablock.

A lot of people reckon neodymium filters are good on Jupiter to enhance contrast.

Hope this helps.

RL

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