Light Pollution Filter

[Stephen]

http://stargazerslounge.com/equipment-reviews/71126-skywatcher-lpr-filter-vs-baader-neodymium-filter.html

[crazyjedi]

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.

Which OIII filter do you use? Most are too heavy for a 6 inch newt. I'm keen to get one for mine but i don't want to waste money.

[crazyjedi]

My Baader UHC-S is good but isn't quite narrow enough to bring out the fainter nebulae. Think i need a decent low power wide angle lens too. If anyone is selling one let me know!!

[spaceboy]

I have read several manufacturer recommendations on the net that OIII filters are recommended for apertures of at least 8" and above. I am guessing Shane has success with his 6" OO because the Castell OIII filter is not as harsh as some of the OIII filters on the market. I too have the Castell OIII filter and find it superb in my 8" & 10" reflectors so if Shane is saying it will work in a 6" scope then I would say go for it as it's a really handy piece of kit for finding those otherwise invisible nebula's.

[granty515]

hi ive been having a little bit of a problem with LP we have the new led lamps in our street lights so filters dont work with them so it may be worth talking to local council to see if they have changed or planing to change to new whiter led lamps , you may save yourself some money ,they are brighter then soduim lamps but do reduce lp alittle and direct light downwards.

[Moonshane]

as Nick says, I use a Castell filter. I bought based on price and also that I wanted a 2" filter. the chart was a bonus as I saw it was not quite as harsh as e.g. the Baader version and quite closely matched the Astronomik one which is at least 3x the price.

all I can say about it in the 6" is that it certainly reveals the veil from my garden which is 9 miles from Manchester and 4 miles from Stockport with a poor sky rated at Bortle 8. other targets like the Orion Nebula show more detail etc. I must do a more thorough comparison of this filter and my UHC castell too, possibly even the Baader neodymium, in the 6" as this might be of interest to many.

[crazyjedi]

Yes a comparison/review would be most welcome!

[crazyjedi]

Just found the Castell OII filter for sale for just £36 - sounds tempting. I've pasted the on-line product description. Can anyone spot the spelling errors? - Hilarious!

Castell OIII Deepsky Filter for 1.25-Inch (31.7 mm) Eyepieces

This OIII filter will allow emission lines of the doubly ionised oxygen (OIII) where most of the light comes from older objects such as planetary nebulae and supernova remnants.

Similarly to the UHC filter, it will also cut off all the light produced by Mercury and Sodium lamps that is important for astronomers in light polluted areas. The result is an astounding visual observation experience: brightness of stars decreased by 2-3 magnitudes, whilst the darker background emphecises the contrast of our main astronomical objects such as nebulae. Details of deep sky objects will plastically stand out from the background, thus producing a photo-like sight of nebulae through larger telescopes (e.g. NGC 6992-6995, Veil Nebula in Cygnus).

[spaceboy]

I agree Shane. While it doesn't look like the castell UHC will become available at www.365astronomy.com anytime soon I would be interested to see how you compare it to the castell OIII in the 6". I have the 2" skywatcher UHC filter and I find it in my 8" reflector to be a lot more harsher on the background sky than the OIII is. From what I am led to believe it is supposed to be the other way around.

[faulksy]

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.

as said i bought a badder oiii filter and fitted it to my 6" mak and it dulled everything due to aperature to small

[spaceboy]

as said i bought a badder oiii filter and fitted it to my 6" mak and it dulled everything due to aperature to small

This is again to the point I made earlier. While all of our intentions are honorable and we are only trying to help. I can understand where the confusion for George has arose. While I may argue the point that a LPR filter has little to no effect for me, given some of the posts I have read on this thread and others relating to the same debate I have to admit that I too have fell foul of my own advice. I should accept that what works or dosen't work for one may not work or work for another. (try saying that fast 10 times )

I fear the problem although a welcome one is that there is simply too many different accessories and brands on the market. Add to that all the variables involved. To try offering accurate advice to someone 90 miles away looking through a different scope, eye piece and filter is near impossible.

Would the Baader OIII work for Shane in his 6" scope with the same success? They are after all both OIII filters! Again would the Castell work for faulksy in his MAK ?

I am sorry if my information has mislead anyone in any way. Unless you live within 5oo meters of my address have a 8" F/5, have an eye full of floaters and look like when observing I would dismiss my advice as not compatible.

This said as I already have a SW LPR I am going to give M110 a go on the recommendation of another member

SPACEBOY

[great_bear]

Would the Baader OIII work for Shane in his 6" scope with the same success? They are after all both OIII filters! Again would the Castell work for faulksy in his MAK ?

When it comes to Narrow Band Light Pollution Filters, aperture isn't really the issue per se, it's exit pupil.

These filters work best with a very large exit pupil - three to six millimeters or thereabouts. The trouble with a Mak is that they only produce exit pupils of 2.5mm or less, and thus can get plunged into near total-darkness when you use such a filter.

Nonetheless, with a clear sky and very dark-adapted vision you may still find some occasional use for a narrowband filter on a Mak from time-to-time.