Astronomik's 2" H-Beta Filter is a superb narrowband emission line filter for CCD imaging applications as well as visual observation. It permits H-Beta emission line nebulae to be transmitted while simultaneously blocking nearly the entire rest of the spectrum where the CCD is sensitive. This filter's 12 nm FWHM (full width at half maximum) enables extremely fast optics when using common CCD cameras. The Astronomik H-Beta 12 nm Visual Filter features a transmission of up to 98%. An additional benefit of 12 nm filters is the improved guide star availability for cameras with a built-in autoguider.