ZWO Hydrogen-Alpha Filter

A 7nm bandpass is narrow enough to isolate the specific light emitted by hydrogen-alpha regions while blocking out most artificial light pollution and natural skyglow. This allows you to capture high-contrast images of nebulae even when shooting from light-polluted urban or suburban environments.

Yes. Because this filter only allows a very specific wavelength of light to pass through, it effectively suppresses the broad-spectrum light from the moon, allowing you to continue imaging nebulae even during brighter moonlit nights.

This is an unmounted 31mm round filter. It is specifically designed for use in filter wheels or drop-in filter holders rather than for threading directly onto a camera lens.

No, this is a narrowband filter designed specifically for emission nebulae that glow at the 656nm hydrogen-alpha wavelength. It will not be effective for broadband targets like galaxies, reflection nebulae, or star clusters.

Standard light pollution filters are typically broadband and only block specific wavelengths of streetlights. This H-alpha filter is much more aggressive, blocking almost all light except for the narrow 656nm band, which provides significantly higher contrast for nebulae but requires longer exposure times.