The Explore Scientific O-III 2" 6.5nm nebula filter is designed to enhance the observation of emission nebulae, even under heavily lit skies. By blocking almost all artificial light, this filter only allows the emission lines of oxygen to pass through, revealing celestial objects that are often invisible to the naked eye. This filter is particularly effective for observing nebulae such as the Cirrus Nebula NGC 6992, which becomes easily visible with a 200 mm telescope, even in urban environments. With a narrow bandwidth of just 6.5 nm, it increases the contrast and sharpness of deep-sky objects, making it an essential tool for amateur astronomers and astrophotographers. Each filter comes with an individual test certificate to ensure its high quality.