The economical Astro-Tech ND9 neutral gray filter reduces the brightness and glare that can mask low contrast details during lunar and planetary visual observing. It does so without affecting the natural colors of the solar system object being observed. It can also be very effective when used with some webcam and DSI-type cameras to reduce the brightness of the Moon to keep from saturating the imaging detector during lunar photography.
The filter is mounted in a standard 1.25" threaded cell. It will thread into the barrel of any 1.25” eyepiece or into the 1.25” nosepiece of webcams, DSI-type cameras, or CCD cameras or filter wheels that accepts 1.25" filters. The filter comes in a hard plastic protective case.
Due to its low 13% light transmission, it works best with scopes 6”-8" and larger. Its price is particularly cost-effective when compared with higher-priced competitive filters of equivalent performance.
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