BST Variable Moon Filter

[Mowbs]

Hi

I recently purchased a BST variable polarising moon filter for my Skywatcher 200p but I am having a bit of a problem using it.

If I screw one of the filters into my eyepiece (I'm using Celestron X Cel's 1.25") then the eyepiece won't fit properly into the eyepiece holder (the bit that came with the filter assembly) I'm assuming the second filter should still be screwed in the eyepiece holder. The eyepiece goes in but doesn't feel secure and doesn't give me access to turn either of the filters to adjust the amount of filtration. The eyepiece sits higher in the eyepiece holder when the filter is screwed into my eyepiece.

I obviously don't want to drop an insecure eyepiece out of the holder when moving the scope.

I contacted the seller and they suggested leaving both filters screwed into the eyepiece holder (one screwed into the other) that does work but it just means I have to remove it along with the eyepiece to make any adjustments.

Has anyone else had this issue, is that just how it is with this type of filter?

Many thanks

[Mowbs]

Just writing this to bump up the post, someone must use a BST moon filter somewhere in this (or any other) universe

[Reeny]

I don't use one - but it looks like that is the only way it will work with the filter set as supplied.

The case is very short, so the eyepiece will be hanging out.

A pint won't fit into a half pint mug - so I can't see any other way around it.

I have a Barlow with a removable screw on lens.

If you had something similar you could try to use that instead of the supplied case.

The Barlow looks like this, and a filter can be screwed into the base before the lens is fitted.

 

I'm not sure what will happen to the focus point without the magnifier lens fitted to compensate.

It won't be a good outcome.

The eyepiece / Barlow assembly will be moved 30mm further away from the tube.

The Barlow will be more a secure holder - but not an ideal solution if you don't need the 2x magnification.

[rwilkey]

You don't need to use the middle bit in Reeny's first picture, i believe it's just an extension tube?