Optolong OIII-CCD 6.5nm (Round 31mm Without Housing) CCD Filter [OPTO-OIII-CCD65-31]

Optolong: Extra Narrow band OIII-CCD 6.5nm filter is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). OIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.[/extract]

• Glass quality Schott glass
• Thickness 2mm
• Surface quality 60/40 standard MIL-O-13830
• Transmission 80% on the line 500nm