Baader Ultra-Narrowband 4.5 nm O-III CCD Filter - 65x65 mm square unmounted

Baader 4.5 nm Ultra-Narrowband O-III Filter

The nebula filter allows for even higher-contrast images in the red spectral range around 502 nm which is so important for astrophotography. Finest detail of nebulae are shown better and stars are suppressed even stronger. The filter can also be used for extreme images of planetary nebulae.

Of course this filters also have the proven Baader anti-reflective coating which reliably prevents ghost images.

Due to the extremely narrow range of only 4.5 nm, a particularly high CWL accuracy (central wavelength) is necessary. That requires greatest skills and only few manufacturers worldwide have the necessary abilities.

Baader Ultra Narrowband O-III Filter