This superb integrated double filter is ideal for Lunar and planetary observation, as well as webcam and CCD imaging of bright targets. This unit actually consists of two polarizing filters - one fixed, and the other mounted above it in a special rotating holder (click picture for detail).

By rotating the top filter you can achieve precise control of the transmission level (how much light the filter allows through to your eye or camera imaging chip) which means the unit functions much like a neutral density filter, except that the cross-polarizer can be precisely and easily adjusted to suit the observing situation (sky transparency, magnification etc).

This is perfect for viewing bright targets such as the Moon (to avoid being dazzled and missing faint detail) and planets. Itīs also very effective for observing double stars where one of the components of the binary or multiple system is very bright and close to the other components. Supplied in plastic storage case.