H-Beta Filter

The Astronomik H-Beta Filter is a premium narrowband emission-line filter designed for deep-sky visual observation of hydrogen-rich nebulae. It isolates the H-beta emission line at 486 nm while blocking the rest of the spectrum, dramatically enhancing contrast between faint hydrogen nebulae and the night sky. With its 12 nm full-width-half-maximum (FWHM) bandpass and exceptional 97% transmission, this filter is ideal for observing challenging objects like the Horsehead Nebula with medium to large aperture telescopes. The filter's diffraction-limited optical performance, parfocal design, and durable MFR coating ensure reliable performance across a wide range of aperture ratios.