Watch Vic Maris of Stellarvue, talk filters with Chris of Chroma, at the 247th meeting of AAS: Chroma Filters at AAS
H-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-Alpha from the SII doublet (671.6nm and 673.1nm).
