Astronomik H-Alpha 6 nm CCD Filter - 1.25" Round Mounted - HA6-1

An extremely narrow emission-line filter, the Astronomik 6 nm H-alpha filter is for CCD imaging work and not for visual or solar applications. It is designed for use with instruments as fast as f/3.5. This narrowband filter allows the h-alpha light from emission nebulae pass through to your sensor while blocking other areas of the spectrum almost completely.

The FWHM of the Astronomik 6nm H-Alpha 1.25” Filter is optimized for maximum contrast between objects that emit H-alpha, such as emission nebulae, and the background sky. While the 12nm is similar in function, the 6nm offers higher contrast gain due to the smaller FWHM. The trade-off is the dimming or eradication of some background stars in the final image. Using the Astronomik 6nm H-Alpha in conjunction with the 12nm H-Alpha filter will provide maximum contrast in HII objects (6nm) while keeping background stars visible (12nm) in the final image.

The Astronomik 6nm H-Alpha filter is a good choice for imaging from light-polluted skies, as it completely suppresses mercury (Hg) and sodium (Na) emissions lines; the main culprits of light pollution.

Please note this filter must NEVER be used for solar observing or imaging. Doing so will cause permanent damage to your eyes.