William Optics STC Astro Multispectra Filter

This filter features a standard 48mm diameter, making it compatible with most 2-inch telescope eyepieces and camera adapters. Please verify that your specific imaging train or eyepiece barrel accepts 48mm threaded filters before purchasing.

Unlike broadband filters that simply darken the entire image, this multispectra filter selectively blocks specific wavelengths associated with artificial light—like mercury and sodium street lamps—while letting over 95% of key emission lines like H-alpha, OIII, and H-beta pass through. This results in significantly higher contrast for deep-sky objects without sacrificing the signal of the nebulae you are trying to capture.

Yes, the double-sided nano coating is designed to be both water and grease resistant, with a water drop contact angle greater than 110 degrees. This makes it much easier to clean off accidental fingerprints or dew buildup without needing harsh cleaning solutions that could damage the optical surface.

Absolutely. The matte black anodized frame is specifically designed to absorb stray light and eliminate internal reflections that can cause ghosting or flare in your final captures. It ensures that the light hitting your sensor is only the light coming directly through the glass.

The filter uses ion-beam-assisted deposition coating on high-quality Schott B270 optical glass, which creates a very hard, stable surface. This process makes the coating highly resistant to environmental changes, humidity, and temperature fluctuations, ensuring it holds up well over years of regular astrophotography sessions.