ZWO H-alpha Filter

The 7nm bandpass is narrow enough to effectively block most light pollution and skyglow while allowing the specific 656nm H-alpha wavelength to pass through. This significantly boosts the contrast of emission nebulae, making them stand out against the background sky.

This is a 2-inch round filter with a standard M48x0.75 male thread. It is designed to screw directly into most 2-inch filter wheels, camera adapters, or eyepiece barrels that accept 2-inch threaded filters.

While it is optimized for astrophotography, it can be used for visual observation. However, because the 7nm bandpass is very narrow, you will need a telescope with a large aperture to gather enough light for a clear view of the nebula.

An 80% transmission rate is quite high for a narrowband filter, which helps keep your exposure times manageable. It ensures that you capture enough signal from the target object without needing excessively long exposures.

Yes, the 1/4 wavefront accuracy ensures that the glass does not introduce distortions or aberrations into your optical train. This maintains the sharpness of your stars and fine details in nebulae across the entire frame.