Light pollution filters - are they worth it?

guggle (Michael) · #1 18-03-2011, 01:28 PM

Living in suburban Melbourne, you could imagine that there is a fair amount of light pollution around. Looking around on various websites, I see that there are light pollution filters available and I was wondering how effective they are.

Does anyone have any experience with these?

Cheers, Michael.

alistairsam · #2 18-03-2011, 01:59 PM

I've been thinking of the same but from asking around at astrocamps, most who own UHC-S filters or similar say differences are not significant enough.

Else it'd have to be narrowband filters.

from my understanding galaxy spectra are too wide to be filtered, but nebulae filter might help.

input from those who own skyglow or pollution filters would be good.

wavelandscott (Scott) · #3 18-03-2011, 02:20 PM

I'd encourage you to do a forum search on filters...You will find a fair amount of material and some comments that might be helpful.

In summary:

#1 Will a light pollution help? Yes
#2 Is it a subsititute for dark skies? No
#3 Knowing what I know know would I purchase a "Light Pollution" Filter? No probably not

Do search the threads...

irwjager (Ivo) · #4 18-03-2011, 08:39 PM

Hi Michael,

I also live in Melbourne about 12K from the CBD and have found my broadband light pollution filter really useful. I was able to get it very cheap second hand so I thought I'd give it a try, but honestly didn't expect too much.

It's a very cheap Seben (do note that this brand will make a lot of people cringe around here

) so I was cautious, but it actually gets pretty good reviews on some German astronomy forums and rightfully so.

In my 8" Newt, M42 has slightly more contrast and it's easier to spot the dust lanes. The Carina Neb is where this filter really shines - with my eyes fully adjusted I can actually see it as you'd expect in an astro photo.
I also found M8 to be easier to see. It also makes other nebs easier to spot.

It does destroy color (my particular filter makes things green), but you wouldn't expect to see much color with an 8" Newt anyway when doing visual.

Hope this helps!

Cheers,

wavelandscott (Scott) · #5 19-03-2011, 12:42 AM

Quote:

Originally Posted by irwjager

Hi Michael,

I also live in Melbourne about 12K from the CBD and have found my broadband light pollution filter really useful. I was able to get it very cheap second hand so I thought I'd give it a try, but honestly didn't expect too much.

It's a very cheap Seben (do note that this brand will make a lot of people cringe around here

) so I was cautious, but it actually gets pretty good reviews on some German astronomy forums and rightfully so.

In my 8" Newt, M42 has slightly more contrast and it's easier to spot the dust lanes. The Carina Neb is where this filter really shines - with my eyes fully adjusted I can actually see it as you'd expect in an astro photo.
I also found M8 to be easier to see. It also makes other nebs easier to spot.

It does destroy color (my particular filter makes things green), but you wouldn't expect to see much color with an 8" Newt anyway when doing visual.

Hope this helps!

Cheers,

While I've not used the Seben (I've got the Astronomik one) I think you are providing good insight.

For me the real issue always was/is that with the light pollution my eyes never get dark adapated...the Light Pollution Filter does help but because I couldn't dark adapt I found the usefulness limited.

For me, if I'm looking for Faint Fuzzies it is much better to drive to a darker place.

bartman (Bart) · #6 19-03-2011, 01:36 AM

For astro imaging are these filters any good ( uhc-s) compared to visual use of these filters?
Just thought I would put this question forward .....
Bartman

Allan_L (Allan) · #7 19-03-2011, 10:19 AM

Found this the other day.
Take it for what its worth:

Quote:

Originally Posted by Shawn Grant

Myth number one: Light pollution filters decrease sky glow caused by artificial lights and enhance all deep sky objects. Yes they decrease sky glow but they also decrease the brightness of stars, star clusters, globular clusters and galaxies making views of them worse. Stars, galaxies and star clusters emit light from all wavelengths including the same wavelengths as street lights which the filter blocks. That is why light pollution filters diminish the view of such objects. Light from emission nebula and planetary nebula has a different wavelength of light then streetlights and the light of a nebula passes right through the filter. So light pollution filters true function is to block sky glow to add contrast making emission and planetary nebula more visible. For now on I will not use the term light pollution filter. They are nebula filters. Always call them that because that is what they enhance. Light pollution filter is a misleading name.

Myth number two: Nebula filters work only in light polluted skies. That is completely false. Nebula filters enhance nebulas no matter where you are, New York City or a thousand miles away form the nearest light source.

Myth number three: Only large telescopes can benefit from nebula filters. For many years Walter Scott Huston wrote a monthly deep sky column in Sky & Telescope. He died a few years ago and the column stopped. In one of those columns Walter wrote about people holding a nebula filter up to their eye to view nebulas like the California, Rosette and others. Without the filter no nebula was seen and with the filter a nebula was seen. If a nebula filter works for the eye it will work with a telescope of any size.

There are so many nebula filters which one should I buy? There are two major types. One called a broadband and the other a narrowband. The narrowband has a few sub types that I will go into later. The broadband (also called wideband) filter blocks the least amount of light and enhance nebulas the least. Some popular brands are Orion Sky Glow and Lumicon Deep Sky. Celestron and many other companies make them as well. Most people confuse a broadband filter as the filter to decease sky glow and enhance all deep sky objects. Basically a do all filter. In fact this is how all companies market their broadband filters. As with myth number one we know that this is false. The real use for broadband filters is to enhance some reflection nebulas, HII regions (nebula) in galaxies such as M101 and M33 and astrophotography of nebulas only. It doesn’t produce dramatic results but can help. You will not use a broadband filter much.

The other type is the narrowband. Some popular brands are the Orion Ultrablock and Lumicon UHC. These filters block out the most sky glow and enhance emission and planetary nebula the most. Narrowband filters do significantly enhance nebula and they work very well. There has been countless times I was observing in an area that the chart says there was a nebula and I couldn’t see one. I screwed on a narrowband nebula filter and the nebula appeared. Even bright nebula such as M42 and M8 show lots more detail with a narrowband filter then without. Planetary nebula shows more detail as well. Many times a narrowband will help in spotting a planetary nebula. Pass the filter between the eye and the eyepiece. You will see the planetary blink. Narrowband filters such as the Ultrablock or the Lumicon UHC do such a good job you can’t go without one. A narrowband filter is just as important of an accessory as an eyepiece, telrad and star charts. Get one!

There are two other narrowband filters that allows less light through then the Ultrablock or the UHC. These are both made by Lumicon and they are call the Oxygen III (O-III) and H-beta. The O-III does a better job enhancing planetary nebula and some emission nebula then the Ultrablock or UHC. Some emission nebula looks a tad worse then the UHC or Ultrablock. The O-III cannot be beat for planetary nebula. The H-beta has a limited use. It enhances only a few emission such as the California and IC 434 making the horsehead easier to see. It will also enhance some very faint emission nebula. Many people call the H-beta the horsehead filter because in many cases it is the only way to see the horsehead nebula.

In summery nebula filters are great if you understand what they do and how to use them. They are for enhancing nebulas only and not other deepsky objects no matter what ads might say. If you were only to get just one get the Orion Ultrablock or the Lumicon UHC. It doesn’t matter which they are both of equal quality and equal price. If you can afford two it would be a toss up between a broadband or the O-III. Personally I would get the O-III. If you can afford three get which one you didn’t choose for just two. For those of you who are serious deep sky observers and can afford it, get all four. I hope this answered a lot of questions and help you make wise purchases and know when to use a nebula filter and when not to.

irwjager (Ivo) · #8 19-03-2011, 11:24 AM

Quote:

Originally Posted by wavelandscott

While I've not used the Seben (I've got the Astronomik one) I think you are providing good insight.

For me the real issue always was/is that with the light pollution my eyes never get dark adapated...the Light Pollution Filter does help but because I couldn't dark adapt I found the usefulness limited.

For me, if I'm looking for Faint Fuzzies it is much better to drive to a darker place.

You're absolutely right - nothing beats a dark sky site. My broadband filter won't really do much for the other faint fuzzies, but the light pollution where I am is *really* bad, so I guess it's easy to notice a difference.

Michael, you're welcome to borrow it (or have an ogle through my scope) and see what you think.

guggle (Michael) · #9 20-03-2011, 08:58 AM

Allan, thanks for finding and posting that review. It was what I was looking for.

Ivo, I might just take you up on your offer.

guggle (Michael) · #10 30-03-2011, 06:18 PM

With many thanks it Ivo (irwjager), I was able to borrow a light pollution filter and see for myself their worth. I was impressed with the level of contrast and sharpness it gave when looking at nebulae. I could see detail that I hadn't been able to before. Looking at stars and clusters didn't really make that much difference though. All it really did was give everything a green tinge.

Given that I wont be able to do dark sky observations very often, I see this as a valuable addition to my meager collection, although, I guess I should ask first, are there different types of LPF's and what are their alleged benefits?

Thanks again to Ivo.

Cheers, Michael.

Fox · #11 01-04-2011, 09:42 AM

Hi Mike. I have an old Lumicon Deep Sky filter. I use it with my 1.25 inch EPs and Genesis and NP127. It's nice with brighter nebulae and on select nights, but I don't use it much. I get best results when the skyglow from where I am isn't too intense, which itself is very unpredictable. Fox

stevemac · #12 01-06-2011, 12:41 PM

Hi all,
Has anyone had any experience with the Ba'ader Moon-skyglow filters? (2") Noting the comments in this thread, I do not see any mention of them? Does that mean "no good?"
Thanks
Steve

nb: i also posted a similar question in the beginners equipment forum

casstony · #13 01-06-2011, 04:18 PM

A zoom eyepiece is very useful with nebula filters - it lets you quickly find the best magnification/exit pupil for your particular observing conditions. I find contrast is best in a limited range from in town. Last night using a 6" f/5 achromat I found an exit pupil of 2.4 to 3.2 was giving the best result on the carina nebula. (12mm - 16mm setting on a hyperion zoom).

ZeroID (Brent) · #14 02-06-2011, 11:56 AM

I have an Astronomik CLS filter and find it improves the view in my LP zone. Not too dark but enough to define Neb Dust clouds that were not visible before.The OIII is better but darker for Nebs obviously but CLS does help and for the price worth it to me. Gives me alternative viewing options.

CoolhandJo (Paul) · #15 02-06-2011, 09:00 PM

I couldn't image at home without my hutech lpr2 filter. It's very good as it doesn't obstruct colours too much.

toc (Tim) · #16 05-06-2011, 07:06 PM

Quote:

Originally Posted by irwjager

Hi Michael,

...

It's a very cheap Seben (do note that this brand will make a lot of people cringe around here

) so I was cautious, but it actually gets pretty good reviews on some German astronomy forums and rightfully so.

Cheers,

I have the seben - I used it once with the C8, and wasnt impressed with the results - I will have to give it a go with the new 12 inch scope I have...