Adjustable brightness control - Set the light transmission from 1% to 40% by turning the filter housing for precise brightness, matching target and sky conditions. 1.25 inch variable polarizing filter - A variable polarizing filter that acts as a dimmer switch for your telescope, enabling smooth brightness modulation. Finer brightness control for better performance - Provides finer control of image brightness compared with fixed-transmission telescope filters, enhancing contrast and detail. Moon and planetary viewing made easier - Reduces the brightness of the Moon or planets to enable a clearer, more comfortable viewing experience. Compatibility and installation - Designed for standard 1.25 inch telescope setups and compatible with common 1.25 inch accessories. Use scenarios - During bright lunar phases, dial down brightness to reveal surface details. - Observe bright planets and adjust brightness to improve contrast and detail. - For planetary imaging, set brightness to optimize exposure and reduce glare.