Light Pollution Filters

[bluenotetim]

Hi Everyone,

I know this is a basic question but just wanted to get everyone's opinion on light pollution filters? Basically do they work? I live next to a large national distribution centre that's lit up like a xmas tree 24/7/365 and am struggling with the dull orange glow. The easiest answer would be to go out to a dark site but its not always possible especially with a 200p so would like to make the best of what I have in the back garden.  What are peoples experiences with these filters? Many thanks, Tim.

[jambouk]

Is this for imaging or visual astronomy?

They certainly work for imaging, but you get what you pay for, and their effectiveness appears to vary depending on what wavelengths are predominant in the light pollution. There was an article recently by Professor Morrision in one of the journals on them.

James

[wxsatuser]

They do work.

My exposures would be no more than 30seconds without but with 5minutes is easy.

I have a mixture of sodium and mercury around here and the Astronomik clip and IDAS P2

both do the business.

M27 in the full glare of football club floodlights, local streetlight glare and sodium from the southcoast towns.

Astronomik CLS  Canon 60Da 2minute subs,

[bluenotetim]

Is this for imaging or visual astronomy?

They certainly work for imaging, but you get what you pay for, and their effectiveness appears to vary depending on what wavelengths are predominant in the light pollution. There was an article recently by Professor Morrision in one of the journals on them.

James

To start with it will be for visual astronomy, I really don't know what sort of lighting they are using as you can't get onto the site . Thanks for pointing me to the article by Professor Morrison, I shall have a read later. Thank You

[bluenotetim]

They do work.

My exposures would be no more than 30seconds without but with 5minutes is easy.

I have a mixture of sodium and mercury around here and the Astronomik clip and IDAS P2

both do the business.

M27 in the full glare of football club floodlights, local streetlight glare and sodium from the southcoast towns.

Astronomik CLS  Canon 60Da 2minute subs,

Wow, thanks for the reply and the image above gives me plenty of hope for my back yard. Cheers

[laudropb]

Lap filters are really only effective for the orange glow you get from sodium lamps, certainly as far as visual observing goes.

[Moonshane]

It depends really what you want to look at. Things with a broad wavelength content like galaxies can only really be improved with darker skies, or to some extent larger aperture, as they are also 'filtered' by a general LP filter as are reflection nebulae (like M78) for the same reasons. If however you want to look at things like the Veil nebula, Dumbell, to some extent M42 etc then UHC and Oiii filters work very well even in LP. At home the Veil is invisible without an Oiii but I can even see it with my 80mm apo with an Oiii and I live within 9 miles of Manchester and within 3 miles of Stockport.

[bluenotetim]

Lap filters are really only effective for the orange glow you get from sodium lamps, certainly as far as visual observing goes.

It seems that they have some orange sodium lamps on site but  I think there are also floodlights there, there is a general orange glow from the site but I can see the sides of some of the larger buildings lit with a white light.

[bluenotetim]

It depends really what you want to look at. Things with a broad wavelength content like galaxies can only really be improved with darker skies, or to some extent larger aperture, as they are also 'filtered' by a general LP filter as are reflection nebulae (like M78) for the same reasons. If however you want to look at things like the Veil nebula, Dumbell, to some extent M42 etc then UHC and Oiii filters work very well even in LP. At home the Veil is invisible without an Oiii but I can even see it with my 80mm apo with an Oiii and I live within 9 miles of Manchester and within 3 miles of Stockport.

I am still fairly new to astronomy ( well as far as owning a decent scope goes)  so I am still aiming for the easiest of targets M57 M31 etc etc Thanks for the advice and I shall start looking at Oiii filters. Cheers

[Moonshane]

It's often quoted that a UHC is the most flexible and useful filter but I o find the Oiii gets used a lot more even with apertures smaller than yours. I rarely ever use my LP filter these days but when I dfo it's often as a planetary filter to tone down the brightness of e.g. Jupiter and Mars a little to allow finer detail to become more obvious.

[bluenotetim]

It's often quoted that a UHC is the most flexible and useful filter but I o find the Oiii gets used a lot more even with apertures smaller than yours. I rarely ever use my LP filter these days but when I dfo it's often as a planetary filter to tone down the brightness of e.g. Jupiter and Mars a little to allow finer detail to become more obvious.

Thank you, Tim

[CodnorPaul]

A filter I find useful for observing from home with only moderate LP is a Neodymium - it lives in my EP when at home.  My UHC filter is next on list and is useful on quite a few objects, then the OIII is least used.  The UHC and OIII really come alive when being used from a darksite.

[spike95609]

Some people say light pollution filters work, others that they make no difference. For visual use I fall into the latter camp. I've got a Baader Neodymium, which is very good as a moon filter, but if it does make a difference to light pollution then to my eyes (which are very good) it's so slight as to be unimportant.

[bluenotetim]

A filter I find useful for observing from home with only moderate LP is a Neodymium - it lives in my EP when at home.  My UHC filter is next on list and is useful on quite a few objects, then the OIII is least used.  The UHC and OIII really come alive when being used from a darksite.

Thanks mate, I haven't come across a Neodymium filter before so a little research is in order !

Thanks again for the reply.

Tim

[gazaddy]

I've just got the baader neodymium filter......then the fog turned up....typical