Polarising filter (1.25")

Polarizing filters are most often used to reduce the brightness of the Moon and planets.By twisting 2 of them together and rotating them on top of each other, you can adjust the transmittance between about 2% and 40%.

The advantage of this solution is that the amount of light reduction can always be conveniently adjusted depending on the magnification or moon phase used. This means that, unlike fixed transmission moon filters, the image will not be too bright or too dim.

TIP: A pair of polarizing filters is most conveniently used by screwing one onto the filter thread of the eyepiece and the other onto the filter thread of the eyepiece. Then you only need to rotate the eyepiece to achieve the desired light transmission.