The SVBONY SV227 is a 2″ H-alpha narrowband filter with a 5 nm bandwidth, designed for deep-sky astrophotography. It isolates the hydrogen-alpha emission line at 656.3 nm, making it well suited for imaging emission nebulae while strongly suppressing light pollution and unwanted sky glow.

5 nm Narrowband Precision

With a narrow 5 nm passband, the SV227 provides strong contrast enhancement for hydrogen-alpha emission while rejecting surrounding wavelengths. This makes it ideal for isolating nebular detail in both light-polluted and dark-sky environments.

High Transmission & Deep Blocking

The filter delivers a peak transmission of at least 90% at the H-alpha wavelength, combined with an optical density of OD5 or greater outside the passband. This deep blocking helps reduce background noise and improve signal-to-noise ratio in long exposure imaging.

Precision Optical Construction

Manufactured using high-quality optical glass, the SV227 features tight parallelism (≤30 arcseconds) to help maintain focus consistency and minimise star distortion across the imaging field.

Standard 2″ Thread Compatibility

The filter uses a standard M48 × 0.75 (2″) thread, making it compatible with most 2″ filter wheels, filter drawers, and imaging adapters commonly used in astrophotography setups.

Spectral Performance

The spectral transmission profile is centred precisely at 656.3 nm, ensuring accurate H-alpha isolation for emission nebula imaging.

Substrate & Coating Details

Carefully controlled substrate thickness and multi-layer coatings help maintain optical flatness and long-term durability under repeated use in imaging trains.

Important Notes

• This filter is not suitable for solar observation.
• Not recommended for optical systems faster than f/4.

Technical Specifications