Which size of filter to go for: 1.25 or 2 inch?

[rwilkey]

I've also seen on here people comparing the baader nd to the skywatcher lpr filter. Is there much between these two other than price?

In my view LPR filters don't work the same way as Moon filters, I have the Baader (ND96 (0.9)) and a Lumicon (ND96 (0.6)) and they are both good on the Moon, however, good ND96 filters can be purchased quite cheaply at £9.99 from places like Skies the Limit and they are just as good to be honest, I prefer to use the ND96 (0.9) for 13% light transmission.

[skir]

Robin, what about variable polarising moon filters like this http://www.scopesnsk...d1.25inch.html. Any good?

[rwilkey]

Hi Skir, yes, polarizing filters are good, and I have both 1.25" & 2" versions, but to be honest, I more often use the fixed density filters because it is less faff. Perhaps I am lazy. But with the variable polarizer you can fit one element in your focuser and one on the eyepiece so to get the right density you can twist the eyepiece in the focuser to get the view you want.

[skir]

Ah! How exactly do the variable type work then? If I bought a 2" version for example would I have to use it with a 2" eyepiece?

[rwilkey]

Hi Skir, not sure exactly how they work, two similar pieces of glass polished and finished in positive and negative directions I should think, but they seem to work very well giving from 1% to 40% light transmission. If you have the 2" version you can only use this with a 2" ep unless you have a 2" focuser on your telescope, then you can use the method suggested above.

[skir]

Right ok, I have a 2" focuser so hat could work ok, thanks for the info.