Will this work?

[Yamez]

This is probably plain stupid and to me it makes sense to work but I just want to check. My x2 barlow doesn't have a thread to put filters on the end, so am i able to put a filter before the barlow glass like this:

[SkyBound]

No reason at all why not...

it makes no difference where the filter is as long as it's between the scope and camera, and you focus with it in that position..

[Charic]

No thread?
I have a Barlow and just checked it with an 11mm TV Plössl?
Can you unscrew the cell from the Barlow,, just the cell, leaving the silver tube in place ,  I can, the cell then goes onto the eyepiece, the Filter, say for example Moon filter screws to the Barlow!

The Barlow factor is less  in this configuration, possibly 1.6x rather than 2x? 
Not sure if this of any help!

[Yamez]

15 minutes ago, Charic said:

No thread?
I have a Barlow and just checked it with an 11mm TV Plössl?
Can you unscrew the cell from the Barlow,, just the cell, leaving the silver tube in place ,  I can, the cell then goes onto the eyepiece, the Filter, say for example Moon filter screws to the Barlow!

The Barlow factor is less  in this configuration, possibly 1.6x rather than 2x? 
Not sure if this of any help!

Not too sure I understand, my Barlow can be split up into 3 sections. The top part  from the silver part and the black bottom part where the lens is unscrews  from the silver part. Are you trying to say the filter can go somewhere inbetween one of these 3 parts? or do I not understand?

[SkyBound]

Just use it as you pictured above, it will be absolutely fine..

[Yamez]

Ok thank you, maybe charic thought it was for use with an eyepiece, I should have stated it was for astrophotography without an eyepiece with the Barlow connected straight to the t-ring adapter. All makes sense now. Thanks guys.

[Charic]

....as Skybound suggests, or when you unscrew the small black cell  that contains the glass lens from the silver section of the Barlow, your left with a thread, you can place the filter there, whilst the cell  itself screws to the eyepiece. 
Yes, for me this is for visual use, but it matters not ( I believe ) where the filter sits in the optical train, for visual or astrophotography.

Looking at your last text,  "putting the filter somewhere inbetween" I'm  actually replacing the cell for the filter, then the  cell attaches to my eyepiece for visual use.

[SonnyE]

Yes that will work fine. I only do Astrophotography, and I use a filter wheel and my cameras mount to the rear of the filter wheel. (DSLR and CCD)

So the various filters can be rotated into the light stream. And like was mentioned, focusing must be checked, because it seems to always be affected when a different filter is selected.