Optolong Moon & Skyglow Filter Optolong Moon & Skyglow filter is designed to darken the background sky by blocking light transmission from skyglow 589nm and many street light emissions from artificial light. Its high efficiency preserves image brightness, reveals more details and increases contrast of moon, galaxies, nebulae and globular star clusters. Main Use Ideally it is quite versatile filter for visual observation and astrophotography on planetary nebula. WARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning. Technical Specifications Substrate: B270Thickness: 1.85mmTave: T>90%Blocking range: 350-1050nmBlocking depth: light pollution line blocking >99%Surface quality: 60/40Transmitted Wavefront RMS: λ/4Parallelism: 30s In the Box Filter Manuals & Warranty Optolong 3-Years Warranty
