Alstar 1.25" Narrowband NBPF Hydrogen-a 12nm Filter - Enhances The Contrast Between Object and Sky Allows You to Take Images Even Under Urban Skies

Metal filter cell threads directly into the 1.25-inch barrel of your telescope eyepiece. Mounted in a nicely anodized housing. The Alstar H-aplha cut-off filter enhances the contrast between object and sky, allowing you to take good quality images even under urban skies. Young stars embedded in the bright red of a nebula - an H-alpha filter is the expert if you want to capture hydrogen nebulae in all their glory. With a bandpass of 12nm, only light above 660nm is allowed into your camera - whether under dark skies or under the sky glow of a city. That means the filter also blocks the infamous stray light and light from mercury and sodium vapour lamps. Astrophotography under a light-polluted night sky can be difficult. The solution is an H-alpha filter. The Alstar H-alpha cut-off filter works to filter out a large part of this light pollution.