Astronomik H-beta Filter

This filter enhances the H-beta emission line, allowing it to pass through nearly unhindered, while blocking other wavelengths. It significantly boosts contrast for dark-adapted eyes, making objects like the Horse Head Nebula observable with telescopes between 10" and 12".

Main Use

The ideal aperture ratio for this filter ranges from f/4.5 to f/6, with an extended range from f/3.5 to f/15. Transmission losses and chromatic distortions are minimal and noticeable only with extremely fast aperture ratios of f/3 or faster. The Astronomik H-beta filter is excellent for viewing large objects across the entire field of view, even with wide-angle eyepieces. It works best with telescopes of 8" (20cm) or larger. Smaller scopes may not collect enough light for effective use. Its high optical quality ensures stars appear sharp, preserving the performance of your telescope.

Other Uses

• Though limited to a few celestial objects for visual observation, the filter excels at highlighting faint H-alpha regions that would otherwise be difficult to see.
• When used with an EOS Clip Filter, the H-beta filter enables DSLR photography even in light-polluted areas.

Suitability

• Visual observation (dark skies): Very good, but limited to specific objects
• Visual observation (urban skies): Not suitable
• Film photography: Variable, requiring long exposure times
• CCD photography: Good when combined with an additional IR-block filter
• DSLR photography (original): Excellent for select objects
• DSLR photography (astro modified): Excellent for select objects
• DSLR photography (MC modified): Good when paired with an IR-block filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Unsuitable

Technical Data

• Typical transmission over 95% at the H-beta line
• Complete blocking of unwanted wavelengths
• Main use: Observing Hydrogen Nebulae
• Moisture-resistant, scratch-proof, and non-aging
• Optically polished substrate that maintains telescope performance (resolution and contrast)
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant to humidity, scratches, and aging effects
• Diffraction-limited; the filter does not degrade optical performance
• Comes with a high-quality, durable storage box