A light pollution filter screws in to the inner thread of an astronomical telescope eyepiece. The lens coatings help block out street/house lights, yet allow light from emision Nebulae to get through. 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 – the ones most commonly emitted by nebulae. Views of galaxies and star clusters are also enhanced, but to a lesser degree
For looking at Nebulae, nothing will beat travelling out of town to dark sky areas. But if this is not possible the light pollution filter will certainly help
Available in 1.25″ or 2″
Purchase Light Pollution filters here http://shop.northernoptics.co.uk/sky-watcher-light-pollution-filter-125–2-1395-p.asp