Variable Polarising (Moon) Filter Query

[Rautospoon]

I have a WO Megrez 90 with a 2" : 1.25" Adapter, a 2" diagonal and and Televue 1.25" and 2" Eye-pieces.

My questions are:

1. Would it be best to get a 1.25" or a 2" VPF?

2. How do you attach and use thIs type of filter ?

3. Any videos about VPF's anywhere.

Many thaks and sorry to be "thick" !

[alan potts]

If I were you I would go for a 2 inch if you can screw it into the diagonal, mine has a thread. if not you are more likely to use shorter F/L on the moon so these are normally 1.25 inch eyepieces. I have one BTW and never use it, I find the moon is no problem above X130-150 in any of my scopes, though if ypo are going to look at it with a small magnifcation it can make you squint a bit.

Alan

[Rautospoon]

If I were you I would go for a 2 inch if you can screw it into the diagonal, mine has a thread. if not you are more likely to use shorter F/L on the moon so these are normally 1.25 inch eyepieces. I have one BTW and never use it, I find the moon is no problem above X130-150 in any of my scopes, though if ypo are going to look at it with a small magnifcation it can make you squint a bit.

Alan

Thanks for the reply. How do you actually "turn it" to "vary" it ?

[Pig]

Im not sure how to vary them if they are not fitted on a camera

Maybe you cannot vary it while its in situ and will probably have to take the eyepiece out a couple of times to get  it set up right

[rwilkey]

Yes, you have to take it out to vary it, it's a bit of a faff, which why I prefer to use fixed density Moon filters.  However, if you have one portion of the VPF on an ep and the other screwed onto the end of the diagonal, you can vary it by just twisting the ep in the diagonal, if that makes sense!

[alan potts]

Robin, what a great idea, never thought of that, I will give it a try.

Alan

[memoryman]

i have a 1.25" variable polarising filter. You can either adjust it before fitting by holding it up against the Moon and turning the lower section (the one without the thread cut into it) until the brightness is toned down to your liking, or fit it to the bottom of a 1.25" EP and adjust it the same way, then put the EP into the focuser.