Sky-Watcher 1.25 Inch Light Pollution Filter - Aluminium

Sky-Watcher

Skywatcher Light Pollution Filter 1.25\""   #20198 + Storage Case\n\nBrand New UK Stock, boxed with full Guarantee\nThese contrast-enhancing anodized aluminium, optical glass filters are designed to block out the wavelengths of light emitted by mercury-vapour light and other common causes of light pollution, whilst providing higher transmission at critical hydrogen-alpha and hydrogen-beta lines than competing filters. Bright, light-polluted skies appear much darker, and the contrast between object and sky is improved significantly. This contrast-enhancement effect is particularly apparent on nebulae. Unlike stars, emission nebulae give off light in a very narrow range of wavelengths. These filters allow maximum transmission of the important wavelengths of H-alpha, H-beta and doubly ionized oxygen \u2013 the ones most commonly emitted by nebulae. Views of galaxies and star clusters are also enhanced, but to a lesser degree. Also improves contrast on reddish planetary detail. .