Very silly question about fitting filters

[BlueMystery57]

Still very much a newbie and I decided to invest in a polarising filter to use with my Skywater Travel 120

Daft question probably - but it just doesnt look right

I screwed the filter onto the bottom of the eyepiece as that was the only place that seemed to have a thread

I then put the whole lot into the prism as normal and tightened the holding screws

Trouble is when its situated like this I cannot adjust the filter without lifting the eyepiece out

Am I missing something daft here as I couldnt find anything on Google about this - its obviously so daft a question that the experts assume you know the answer

Thanks

[ronin]

Don't have a polarising filter - no filters - but I have oftan thought the same thing = Once in place you cannot adjust.

Well you can, you rotate the eyepiece and then also the filter slowly to get the polarising operation you want.

When you say put the whole lot into the prism I am guessing you mean a prism diagonal?

If rotating the eyepiece is the answer then you will likely have to check focus when altered.

[Gazabone]

No, that's pretty much it and with a polarising filter, relatively small adjustments make quite dramatic changes to the view. Personally I don't screw the ep in until I've found the required adjustment to the polariser but I only use the polariser on white light solar observing using a Herschel wedge.

There is the option of resting the filter on top of the ep to look through if you have enough eye relief (most ep will allow you to do this) but you do run some risk of it slipping off. May enable you to get the adjustment to your satisfaction before threading it on to the bottom of the ep and using it "properly".

[BlueMystery57]

thanks people - at least Im not going mad and missing something here  

[Stu]

Are you talking about the variable polarising filter which has two elements?

If so, you can put one part into the barrel of your diagonal and the other into the eyepiece, that way you can just rotate the eyepiece to get the adjustment. Leave the eyepiece unclamped until you are happy, then clamp it.