Centered on the 656.3nm wavelength and passing an extremely narrow bandwidth, the 31mm round and unmounted Alpine Astronomical 3.5nm Ultra-Narrowband H-alpha CCD Imaging Filter is ideally suited for use with full-frame CCD and CMOS imaging sensors on optical systems, including telescopes and astrographs of all configurations and apertures, ranging from a super-fast f/3.5 to a more moderate f/10.
Planeoptically polished and dielectric anti-reflection coated, this filter uniformly passes the maximum amount of the bandwidth possible to virtually eliminate halos, reflections, and ghosting to reveal details of wispy nebulae and dim stars that filters with wider bandpasses cannot resolve. It also completely rejects light pollution and blocks longer interfering wavelengths, enabling even the faintest deep-sky objects to be imaged regardless of where you are located or whether the moon phase is normally unfavorable. This version of the Ultra-Narrowband H-alpha filter is offered here as an unmounted 31mm round option for custom applications and imaging systems.
This filter is intended only for deep-sky astroimaging with CCD systems, and should never be used for direct solar viewing or solar photography as permanent injury to your eye and equipment can occur, up to and including blindness.