1.25" inch fit rotating-mount variable polarising filter unit is perfect for controlling brightness when making Lunar or other bright target observations.

(Please note: although these filters can be adjusted to provide greatly reduced transmission the filters are not suitable for solar observation without an additional solar observation filter).

Two identical polarising filters are mounted one above the other - the front filter is set in a smoothly rotating mount. By rotating the first filter the light passing through the stacked pair can be modified anywhere between 1 to 40%.

The filter is also a very effective way of controlling the image brightness and getting workable exposures when taking webcam or CCD images of bright targets.

Black anodised aluminium mounting. Supplied in dust-proof plastic case.