Precisely ground, polished, and individually coated to ensure consistency for bandpass centering, transmission, and out-of-band blocking, this 2" filter-threaded eyepiece Baader 8nm Sulfur-II Narrowband CCD Filter from Alpine Astronomical is ideal for imaging in the deep red light of the 673nm Sulfur-II bandwidth. Its narrow 8nm bandpass selectively isolates the S-II wavelength, blocking all others, allowing you to capture the tight emission line regardless of the moon phase and light pollution. The anti-reflection coatings are designed to maximize light transmission uniformly through the filter to limit distortion and halos, while blocking IR radiation that can cause ghosting when using imaging sensors that are sensitive to those wavelengths.
When stacking multiple images using the other two most popular wavelengths of h-alpha and oxygen-III, users are able to concentrate on three distinct colors to produce brilliant composite images of the sun, nebulae, planets, and other astronomical objects. The filter is mounted in an aluminum frame that has been threaded to fit standard 2" eyepieces and accessories for projection and afocal imaging techniques.
This filter is specifically designed for use on imaging cameras and is not safe or intended for direct solar viewing. Using this filter for direct solar viewing can result in serious eye injury, up to and including blindness.