Astromania 1.25" Variable Grey Polarizing Filter

•  Adjustable polarizing filters are the luxury version of Moon filters. It is composed of two filters that can rotate one relative to each other. Rotating one filter relative to the other continuously adjusts the amount of darkening.
 
•  Most polarizing filters allow light transmission levels from 1% to 40%. They can be used to set the optimal balance between light level and contrast for the size of telescope you are using.
 
•  It is therefore particularly useful in observing the Moon where it is necessary to change the transmissivity of the filter as a function of magnification with which you look at the Moon. In fact, with increasing magnification, the light that reaches the eye or the recording camera decreases and then the transmissivity of the filter must be increased.
 

You often find considerable differences in detail brightness on objects. This is particularly noticeable when observing:

- Moon craters which are close to the lunar terminator
- Stellar spot and faculae. Caution: only to be used in association with an appropriate filter on the front of your telescope!
- Details on planets