H-Beta Filter
Astronomik
From $99.95
3 stores
In stock
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.
Specifications
| Filter Type | Narrowband Emission-Line |
| Full-Width-Half-Maximum | 12 |
| Application Range | f/1 |
| Transmission Range | 480 |
| Optimal Aperture Ratio | f/1 |
| Central Wavelength | 486 |
| Glass Thickness | 1 mm |
| Coating Type | Astronomik MFR |
| Peak Transmission | 97% |
| Minimum Telescope Aperture | 8 in |