Alstar 1.25" Narrowband NBPF Hydrogen-a 12nm Filter - Bundle with - 1.25" 0.5X Reducer Corrector

Alstar 1.25" Narrowband NBPF Hydrogen-a 12nm Filter. 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. This convenient filter only allows wavelengths above 660nm through, which means it blocks a large part of the scattered light and also blocks the light from artificial mercury and sodium-vapour lamps. 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. 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. Metal filter cell threads directly into the 1.25-inch barrel of your telescope eyepiece. Mounted in a nicely anodized housing.

• 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
• Intended for use with with longer focal ratio telescopes and eyepieces of narrow to moderately wide apparent fields of view
• Free light transmission: 22.5 mm lens aperture; Can be used with additional spacers which is available separately to achieve further focal reduction