The H-alpha CCD 12nm filter is designed to let precisely pass only the H-alpha line, one of the most important frequencies emitted by faint objects such as nebulae. Due to the very narrow band, this filter generates a high contrast with the complete removal of light pollution making possible long exposure photography also from suburban places. The H-alpha CCD 12nm filter is suitable for use with monochrome CCD cameras because the color models haven't the necessary sensitivity to work well with these filters.
How to use the filters: The filters are available in two diameters: 31.8mm (1,25") and 50.8mm (2") . These standards are commonly used by telescopes and their accessories. The filters can be used with a CCD or a a DSLR camera (using appropriate photo adapters), but also screwed to optical accessories such as eyepieces or diagonals. When you choose the version of your filter, be careful to choose the diameter compatible with your equipment.
