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Astronomik CLS Filter

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Hi Guys

First post so be kind :clouds2:

(apart from the welcome)

I am considering adding an L/P filter to my kit and am looking at the Astronomik CLS 1.25 for visual & pics.

My location is around 3 miles from Nottingham City Centre so L/P is about average and I get around 15 secs of exposure before the pink glow starts to show.

So anyone out there own this L/P and can give me any positive or negative feedback on this L/P or indeed any other L/P Filter to consider.



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Hi Alan,

Ant once owned the CLS and kindly gave it to me to borrow for a few weeks. It's certainly the filter everyone wants. And a lot of people swear by it.

You only have to see the results other astronomers get using this filter to know its the real deal. With the right setup you couldn't go wrong with this filter.

My own personal opinion is that it all depends on your setup, thats crucial. I think that as filters go, it's too severe and cuts off too much light to make it truly useful in a small aperture scope for visual or photographic use. I tried it using a Skywatcher 80ED from my heavily light polluted skies and yes the light pollution vanished but so did everything i wanted to see. Actually I couldn't see a thing with it, I was far better off with no filter.

It's the same with the imaging. I image unguided using an EQ6, which means the most I can only hope is an exposure of 30-60secs through the C8 with reducer or 2mins with the 300mm telephoto. In both cases the CLS filter drastically reduces the useful light to the point the 30sec images were useless. The unfiltered images showed more detail but with a very orange sky. But i had more luck processing out the light pollution to reveal the detail, whereas the CLS images, no matter how much processing i did, still showed nothing worthwhile.

Basically the people who rave about this filter are either doing guided photography using decent mounts like the GPDX/SS2K and with exposures of 3 mins plus. Or they are observing visually using a light bucket. I'm sure there will be some disagreement but I don't think this a filter to use visually with the ubiquitous 80mm refractor which is everywhere now. But The CLS would be a great filter if you plan on doing long guided exposures or you are planning on using it visually with a 6" plus scope. If you plan on doing neither of those I would recommend the Baader Neodymium. It's the filter I use personally and it's one of the best things I've ever bought.

Just my opinion and almost certainly alone in thinking that too.

Ant, may have a different take on this, plus he has far more experience with the CLS filter.



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Thanks Russ

Lot`s of good stuff there.

I also image unguided on an EQ5 so my exposure times are pretty much the same as yours,maybe nearer the 30sec mark

My scope is a 200mm Newt so maybe get some visual use but I also have a ST80 for quick set up session :clouds2: which as you say would not be able to see much with this filter on. I think I may hold back on this until I start guiding and get exposure times of a few minutes.

Nothing left in the old piggy bank at the moment but would love to upgrade to a Skyscan EQ6 with sbig or something like that.

I will keep buying that lottery ticket :clouds2:



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