Light Pollution Filter

[George!]

Greetings fellow astronomers,

I am looking to buy a cheap light pollution filter for my Skywatcher 200p Dobsonian. I have one in mind (see link bellow).

First Light Optics - Baader Neodymium Filter

Many Thanks for any replies,

[spaceboy]

I read good things about this filter but it may pay you to do a little research as I also read on several sites that the Neodymium and SW LP filters are indiscernible. http://stargazerslounge.com/equipment-reviews/71126-skywatcher-lpr-filter-vs-baader-neodymium-filter.html

At £20 for the SW filter I know which I'd rather have

HTH

SPACEBOY

[Vali x]

i am happy with this filter, it really cuts down LP. i still wonder what outcome i might have if i stack it with Baader UHC S, but in a near future. i believe is a good choice.

[crazyjedi]

I got a cheap LPR filter a couple of years ago and I don't find it very good. I'm not sure of the brand now but it didn't seem to help much with my nasty orange sky glow. I have the Baader UHC-S and it's pretty good

[spaceboy]

I got a cheap LPR filter a couple of years ago and I don't find it very good. I'm not sure of the brand now but it didn't seem to help much with my nasty orange sky glow. I have the Baader UHC-S and it's pretty good

CJ what kind of objects were you looking at ? Most LPR filters are intended for apertures of 6" and below so you should have seen some improvement on there intended targets.

George it may sound stupid but what is it you want the filter for ?

SPACEBOY

[George!]

CJ what kind of objects were you looking at ? Most LPR filters are intended for apertures of 6" and below so you should have seen some improvement on there intended targets.

George it may sound stupid but what is it you want the filter for ?

SPACEBOY

I'm on a hill so i can see a massive orange glow from the motorway and in summer the sun setting.

[spaceboy]

LP filters are only for use on nebula's and will have next to none if any effect on anything else. While they will darken the sky and remove LP they also darken everything else with the exception of certain nebula's. LPR filters would have no real effect in a 200P as they are more often intended for use in smaller aperture scopes. UHC & OIII filters can be used to good effect in scopes 8" and above but again will only improve views of nebula's.

The whole light pollution reduction label can be a some what confusing description to the beginner. Yes they do reduce LP but not in the way most people believe and unfortunately the only cure for the orange glow of light pollution is to travel to dark skies. You will still be able to use your scope effectively in urban areas but the background sky will usually have a light grey appearance to it through the scope.

[George!]

LP filters are only for use on nebula's and will have next to none if any effect on anything else. While they will darken the sky and remove LP they also darken everything else with the exception of certain nebula's. LPR filters would have no real effect in a 200P as they are more often intended for use in smaller aperture scopes. UHC & OIII filters can be used to good effect in scopes 8" and above but again will only improve views of nebula's.

The whole light pollution reduction label can be a some what confusing description to the beginner. Yes they do reduce LP but not in the way most people believe and unfortunately the only cure for the orange glow of light pollution is to travel to dark skies. You will still be able to use your scope effectively in urban areas but the background sky will usually have a light grey appearance to it through the scope.

So what am I best getting for my 8" Dob to reduce orange glow and enhance darkness sufficiently?

[spaceboy]

What objects in the sky do you want to look at?

[George!]

What objects in the sky do you want to look at?

The Moon and M42 mainly and probably Antares

[lw24]

LP filters are only for use on nebula's and will have next to none if any effect on anything else. While they will darken the sky and remove LP they also darken everything else with the exception of certain nebula's. LPR filters would have no real effect in a 200P as they are more often intended for use in smaller aperture scopes. UHC & OIII filters can be used to good effect in scopes 8" and above but again will only improve views of nebula's.

The whole light pollution reduction label can be a some what confusing description to the beginner. Yes they do reduce LP but not in the way most people believe and unfortunately the only cure for the orange glow of light pollution is to travel to dark skies. You will still be able to use your scope effectively in urban areas but the background sky will usually have a light grey appearance to it through the scope.

This only applies for UHC/OIII filters. Light Pollution filters, such as the Skywatcher Light Pollution filter only cut out wavelengths of light emitted from Sodium and Mercury street lights, therefore reducing light pollution.

The Skywatcher Light Pollution filter can be used on any objects.

Clear Skies

[spaceboy]

This only applies for UHC/OIII filters. Light Pollution filters, such as the Skywatcher Light Pollution filter only cut out wavelengths of light emitted from Sodium and Mercury street lights, therefore reducing light pollution.

The Skywatcher Light Pollution filter can be used on any objects.

Clear Skies

While I agree with that LPR filters cut wavelengths of light emitted from Sodium and Mercury street lights and will do so effectively improving sky contrast they only work if you have these type st lights within a 10 mile radius around where you are observing from. Sodium and Mercury street lighting are not as common as they were in the days the LPR filters were developed and so the effectiveness of the filter is now limited to smaller scopes showing no real improvement as quoted by Crazyjedi and myself in "larger" scopes. The LPR filters are wideband and so allow more selected light to pass through the filter. While galaxies and the like have similar wavelengths to modern street lighting there is no real improvement to be seen. It is for this reason the Baader UHC-s filter shows some improvement as although sold as a UHC filter it is in effect a wideband filter allowing more light pass than say a lumicon UHC filter.

My advice to George is to get a polarizing filter for use on the moon and Antares. The moon is itself causing light pollution and that is why the views are washed out. A simple moon filter will solve these issues but if you are suffering the glare of bright stars the polarizing filter will offer more versatility. Although I have found unfiltered viewing of the orion nebula to offer more pleasing views than any filtered ones should I have to choose a filter it would most likely be a UHC as this could be used on other targets such as M27 & M57 as well.

[Moonshane]

I have a Baader Neodymium filter. I use it infrequently, mainly on the moon where more than 50% illuminated and sometimes on Jupiter. Generally though I prefer unfiltered views if it's possible to see the target well without one; although this relates more to narrowband filters like Oiii and UHC. A light pollution filter is not in my experience a 'magic bullet' but has its uses. the narrowband filters however, are more useful and tend to reveal more objects for me anyway (but not galaxies which emit every wavelength of light and therefore are not really enhanced by anything other than more aperture, darker skies or both).

with your scope, I'd possibly consider a UHC filter or Oiii filter and the Castell ones are very good. I have both in 2" and use the Oiii more.

you don't really need a filter for the moon, just give it a minute or two and as your pupil contracts, the brightness effect will diminish; a bit like coming out of your hotel room on holiday with no shades.

as others have said, if you can get away from the bright lights then this will have a more dramatic effect upon what you can see than will any filter.

[Moonshane]

ps I should add in case it was not clear from other posts that filters (the clue is in the name ) block (filter out) certain wavelengths of light. therefore they do not make anything brighter or even increase the intrinsic contrast of an object, they simply remove some of the competing wavelengths and thus make the effective contrast/brightness higher. an analogy I have just thought of is the line of soldiers who are all equally apparent and blend together. when a volunteer is asked to step forward and everyone steps back, the effect is that the one solder who stands still now appears more obvious than the rest even though nothing has changed in him. to me this is how filters work.

[JamesM]

If you are still considering the Baader filter, its other advantage is that it has a protective coating that allows you to clean without fear of damaging the coating - I don't believe the others have this hardened coating.

When the moon is up above 50%, I use that time to study the moon or choose double stars and open/globular clusters which don't suffer under light pollution. The best way to improve viewing of any Deep Sky Object (DSO) to be honest is to find an observing site away from street lights etc - it does make a huge difference.

James

[swamp thing]

The Skywatcher Light Pollution filter can be used on any objects.

Clear Skies

You "can" use it on any object, but it will have no effect on Galaxies and star clusters, as it blocks light from them.

Galaxies and star clusters emit light on all wavelengths of the spectrum including the same wavelengths as streetlamps, so block the streetlamps, block light from Galaxies and star clusters.

As Shane said the only way to improve views of Galaxies and star clusters is darker sky or bigger aperture.

Regards Steve

[George!]

Very confusing information you all have there but I guess very useful!

Can someone put just one down instead of a choice as its very confusing - plus the link if so on FLO.

Many Thanks for all reply's,

[Moonshane]

this would be my choice Castell OIII Deepsky Filter for 2-Inch Eyepieces [Castell-Doiii2] - £46.56 : 365Astronomy: Discovery for every day!. I bet it will get more use than a LP filter.

[George!]

this would be my choice Castell OIII Deepsky Filter for 2-Inch Eyepieces [Castell-Doiii2] - £46.56 : 365Astronomy: Discovery for every day!. I bet it will get more use than a LP filter.

In a 1.25" perhaps and on FLO if possible?

[evilgeenius]

I recently bought a Neodymium Filter and it really helps a lot.

I have a street light a few meters away from where I observe and the Neodymium Filter i recently bought helps me lot, especially when I am pointing in or around the direction of the street light. Without it my long exposure images just come out glowing red.

[spaceboy]

Can someone put just one down instead of a choice as its very confusing - plus the link if so on FLO.

:D:D welcome to astronomy it's nothing but confusing. Refractor, reflector, goto, no goto, filter, no filter, Az mount, EQ mount and then there's ep's that work well in one scope but don't necessarily work in another.

Don't panic it is a large learning curve and we have all had to go through it at some point. The confusion arises from the fact that so many members and all have different scopes, live under different skies, perceive things at the eye piece differently and have different demands from their equipment. While 2 people may have the same filter they may not have the same scope or levels of light pollution so it's only natural the opinions will be varied. This is why it was suggested in one of your other threads that you take it easy and get a little more knowledge before going out spending money on equipment that may never get used. If you can join a local astronomy club and ask if you are able to look through their equipment. Most astronomers understand and will do their best to help. I have seen a few threads on SGL where beginners have been left a little bemused by the fact that galaxies look nothing like the pictures in astronomy magazines or that Saturn is the size of a pea. There is no rush the stars will still be.... sorry the clouds will still be there tomorrow.

SPACEBOY

[crazyjedi]

I think the above post by spaceboy is probably the best advice and sense you'll ever hear. You need to know what's best for you looking through your scope under your sky so unless you have a neighbour with the same scope whom you can compare notes with it's very difficult to pick out what's best for you. The wide range of opinions here are all valid but may not be relevant to you. My sky above is awful for light pollution but my scope is only a 6 inch newt hence i can't go for the heavy duty filters but that's me. Hope you can pick out something useful from the above info. I'd take note of the advice from those who have similar scopes to your own.

Good luck

[Moonshane]

I agree that Nick's post makes perfect sense as does Rob's, but I regularly use both Oiii and UHC filters with my 6" newt to good effect. With the Oiii and in poor light pollution (Bortle 8) I can see the Veil, and various other targets requiring a filter.

[philhas]

In a 1.25" perhaps and on FLO if possible?

Try this

First Light Optics - Baader Neodymium Filter

[Spikey]

Or also from FLO in 1.25" First Light Optics - Skywatcher Light Pollution Filter I'm told there is not much difference to the Baader apart from the price of course.