Confused about CLS filters

[gataki]

Hi,

I'm stuck here in the UK under London's light polluted skies for rather longer than I planned so I want to get a filter that is suitable for imaging, but having read up on LP filters and discovered that the Astronomik CLS filters are recommended I now discover there are two types and I don't know which one would be best?

There's this one, the EOS clip fit - which would be OK as I plan to use it with an EF lens rather than the EF-S kit lens. Or this one, the 2" - which would presumably be useful if I wanted to use it when I wasn't imaging. (Well, trying to. )

Could anyone offer any advice as to which (if either) would be better - and why? And if neither are suitable - maybe an alternative?

Thanks very much,

Liz

[steve51450]

hi

the cls is in 2 types

cls none ir blocked

cls ccd ir blocked

if your camera/ccd is ir blocked you dont need the expense of the ccd version

as for which type/size, that will depend on what you wish to image through

If you are imaging through a scope a lot of the time the standard 2" filter will screw somewhere or other (bottom of a focal recucer, field lattener / mpcc etc)

also if you do then move on from dslr imaging to ccd imaging you can take this filter with you into your new set up.

if you are going to image via camera lens a clip in might be better as its sits nice and snug on the camera and serves as a dust cover.

i hope this helps

steve

[Deneb]

hi

Well the the 2" version, I would think it threads into a bottom 2" eyepiece barrel or ccd camera. Maybe just for Visual use - please correct me if wrong !

The EOS CLS clip's directly into your canon - mainly phasing out LP for imaging, thus you can connect your eos to your telescope focuser with the appropiate canon adaptor. I would thought this one would be more relevant to you.

[Tim]

If you have EF lenses then I would get the EOS Clip filter. It means you dont have to worry about getting spacing right with an in line filter, and you can also take widefield astro images just with camera lenses as well as through the telescope.

I have both versions incidentally, and wouldn't consider using the 2" with my EOS cameras.

As for visually, the CLS is quite a harsh filter, I have never tried visual observing with it, but through the viewfinder of the camera, everything is cyan/blue. I dont know if there is a more appropriate filter for just visual work, but somebody will know here.

TJ

[gataki]

Hi Steve, Deneb and TJ,

Thanks very much for all your helpful replies.

Actually, thinking about it, I'm sort of used to our funny coloured sky and am much more likely not to need it for visual use. I seem to have moved over to the 'dark side' and tend to look at things on my laptop screen more now anyway!

I'm not quite sure I understood this though:

the cls is in 2 types

cls none ir blocked

cls ccd ir blocked

if your camera/ccd is ir blocked you dont need the expense of the ccd version

Is the Astronomik CLS Light Pollution EOS Clip Filter the one I need or are there different types?

Thanks again.

Liz

[steve51450]

Liz is your dslr modded or not

if your canon has not been modded the standard eos cls clip will be fine

if its modded and has the filter taken out you need the eos cls clip ccd filter

if its modded and a replacement baader filter has been installed you need the standard cls eos clip

i think the difference is £20 to £30 so you could always be safe and order the astronomik cls eos clip ccd filter anyway

steve

[gataki]

Thanks Steve for explaining that - my Canon isn't modded so it's just the standard one that I need. Excellent!

Well, some clear skies wouldn't go amiss ...

Liz