Optolong OIII CCD 18nm 2" Mounted Filter

Optolong OIII CCD 18nm - 2” Observational Filter!

Optolong OIII CCD 18nm 2" mounted filter is your perfect companion for nebula observation. Designed to isolate an 18nm bandwidth of light centered at 500nm, it highlights the vivid OIII emission lines while cutting out unwanted wavelengths. This includes artificial light from mercury vapor and sodium vapor lamps and the natural skyglow caused by atmospheric oxygen.

With its focus on the OIII wavelengths at 495.9nm and 500.7nm, this blue-green filter brings celestial wonders to life. Ideal for capturing the intricate beauty of planetary nebulae and supernova remnants, it pairs seamlessly with H-alpha filters to deliver stunning, detailed images. The result? Breathtaking visuals with natural, RGB-like colors that truly showcase the cosmos.

Perfect for visually exploring most emission nebulae, planetary nebulae, and supernova remnants, the Optolong OIII filter excels in various conditions. It’s especially effective for observing bright nebulae like the iconic M42 Orion Nebula, even in areas with heavy light pollution.

Pair this filter with a large-aperture telescope under clear, dark skies with good seeing conditions for the best results. While narrowband filters don’t eliminate light pollution or increase an object’s brightness, they significantly enhance the contrast between the nebula and the night sky, bringing out stunning details without artificially brightening the view.

Quality Filter Materials:

• Schott B270 optical glass substrate material from Germany, 1.85mm thick

• CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture; Laser-engraved to prevent fading

• Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition

Optolong Filter Manufacturing Processes and Parameters

• Filter substrate is fine-optically polished to 1/4 wave and

• Surface quality, according to MIL-O-13830, is 60/40

• 90% transmission at major O-III lines at 495.9nm and 500.7nm.

• Na (Sodium) at 598nm, 589.6nm, 615.4nm, and 616.1nm.

• Hg (Mercury) at 435.8nm, 546.1nm, 577nm, and 578.1nm.

• High value transmission of pass-band and optical density of off-band is assured through Optolong’s planetary rotation system, a homogenous and precise coating procedure

• Thin metal cells have a clear aperture of 45mm for 2” filters

• Each filter comes with a plastic case with high pressure EVA case lining

About Optolong

Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.