A light pollution filter that won’t break the bank

[Astro74]

Has anyone got a recommendations for the above , I’ve heard the badder neodymium is a beauty but is it any better than a budget one for light pollution in Suburban Lancashire using a Mak 127 ? 

[Louis D]

Option one would be a generic Moon & Sky Glow (Urban Sky) filter which are pretty close to the same as the BN at a fraction of the price.  This will cut yellow and orange completely and dim some green.

Option two would be a Svbony CLS filter.  It completely cuts all light from green to orange leaving only blue and red.  It's like using a hammer to drive a tack, though.

Option three would be a Svbony UHC filter.  It's a bit narrower in the blue and red parts of the spectrum increasing contrast on nebula even further than the CLS.

Take a look at this post of mine about LP filters from a couple of months ago.

Here's some various filter spectral images from Star Hunter and myself to see what gets cut and what remains.

Edited February 5, 2023 by Louis D

[Astro74]

Any suggestions for the option 1 ? 

[ONIKKINEN]

Visual or imaging?

If imaging, what type of imaging? For planetary and lunar, not important of course.

[Ricochet]

56 minutes ago, Astro74 said:

Any suggestions for the option 1 ? 

For a neodymium there are only two options, the Baader and the generic copy. If you don't want to get the Baader then get the generic one from wherever it is cheapest, which was eBay direct from China when I bought one. However I do not consider these filters to be light pollution filters but lunar and planetary filters. With the advent of LED lighting, there is not really a lot of light pollution filtering that you can do.

 

[Louis D]

1 hour ago, Astro74 said:

Any suggestions for the option 1 ? 

Here's the Datyson Moon & Skyglow from ebay for under 3 GBP.  How wrong can you go for that money?

[Ratlet]

Just now, Louis D said:

Here's the Datyson Moon & Skyglow from ebay for under 3 GBP.  How wrong can you go for that money?

As a fringe benefit, that filter gives a good boost to contrast for planetary viewing (and a great boost when combined with a yellow, if you don't mind the colour cast).

[Franklin]

19 minutes ago, Ricochet said:

With the advent of LED lighting, there is not really a lot of light pollution filtering that you can do.

Very true, I use the Neodymium for a touch of contrast improvement for lunar/planetary but it won't cut the LED out of the sky. Maybe a Broadband UHC would be better for the OP. My Baader UHC-S does darken the sky quite a lot but also dims the stars as well, so??? The Astronomik UHC-E is said to be very broadband but I've not tried one myself.

[Astro74]

Sorry Im a bit lost in all this - just after a decent finder to block out street lights - are we saying stick to the badder ? 

[Louis D]

Are your local streetlights low pressure sodium (yellow-orange) or LED (broadband white)?  The former can be effectively filtered while the latter cannot.

[Astro74]

Tbh I’m not sure I think led 

[Louis D]

I tried out several filters on the Orion Nebula (M42) tonight in my 6" f/5 GSO Newt under my Bortle 6/7 skies before the full moon overwhelmed everything, and the Svbony UHC struck the best balance between seeing stars and nebula and seeing only nebula.  The Lumicon OIII did a slightly better job at improving contrast by making the sky background even darker without attenuating the nebula significantly (by blocking H-beta).  My Zhumell Urban Sky (Moon & Sky Glow) filter didn't do much to block light pollution.  Maybe a bit, but not enough to want to continue to use it.

Based on that, I would recommend the Svbony UHC for certain as a light pollution filter when viewing nebula.  The Svbony CLS is going to pass a bit more blue and red while still blocking all green/yellow/orange (where the majority of light pollution resides), so it should perform similarly.

For galaxies, which emit broadband light similar to LED lighting, dark skies are the only real answer.  You can try a UHC/CLS filter on them, but don't expect miracles.