The StarGuy O-lll 1.25" Nebualae filter is designed for visual
observation of emission nebulae, particularly planetary nebulae. This filter passes only the 2 wavelengths of ionized Oxygen of light so that even the faintest details can be observed. The view if exceptional to very edge of the field of view with this high quality filter. The optical quality of your scope will be enhanced by these O-lll Filters with the industry's best light transmission of nearly 100% . Use of a large aperture scope is suggested. The StarGuy O-lll Filters are best used for dark sky visual observation and DSLR photography, yet it will enhance some nebulae views in brighter skies. This is the best filter for the Veil Nebula. For use with CCD photography, we recommend an IR block filter.