The Optolong OIII 6.5nm CCD Filter (2″) is designed to isolate the critical Oxygen III emission line at 500nm, making it indispensable for high-contrast imaging of planetary nebulae, supernova remnants, and star-forming regions. Its extra-narrow 6.5nm bandwidth allows faint OIII structures to emerge from even the most light-polluted skies.

Built for advanced CCD and monochrome imaging, this filter excels when paired with H-Alpha and SII filters to recreate false-color SHO compositions akin to the iconic Hubble palette. Its ultra-thin filter cell is CNC-machined from black anodized aero-metal, ensuring mechanical precision and durability without adding optical stress.

Thanks to Optolongs planetary rotation coating system and ion-assisted deposition technology, the filter delivers high pass-band transmission while aggressively suppressing off-band lightincluding skyglow and emissions from mercury and sodium vapor lamps. Whether you’re imaging from a city or a remote dark site, this 2″ OIII filter will take your narrowband captures to the next level.

• Filter Type: Extra Narrowband OIII
• Center Wavelength: 500nm
• Bandwidth (FWHM): 6.5nm
• Transmission at OIII Line: