OPTOLONG Filter H-Alpha 7nm SII-CCD 6.5nm OIII-CCD 6.5nm Narrow Band Astronomy Telescope Filters Kit for Deep Sky 1.25″ Mounted
Quality Filter Materials:
- Schott B260 substrate material from Germany, 2.0mm 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
Filter Manufacturing Processes and Parameters:
- Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
- Surface quality, according to MIL-O-13830, is 60/40
- 80% transmission at OIII line 500nm (at SII line 672nm; at H-alpha 656nm)
- Infrared wavelength 700-1100nm cut-off
- 0.1% transmission Hg at 435nm and 578nm
- 0.1% transmission Na at 589nm
- 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 26mm for 1.25″ filters
- Each filter comes with a plastic case with high pressure EVA case lining
- These Optolong 1.25″ Filters are made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength, or CWL. The filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted; black anodized, and then laser engraved. The result is a super thin filter cell that will produce a clear aperture of 26mm.
- The Optolong H-Alpha 7nm is an extremely narrow emission-line filter that works by allowing a 7nm bandwidth of light, centered on the 656nm wavelength through, and blocking the transmission of contrast-killing light pollution wavelengths. Wavelengths that are responsible for natural light pollution, or skyglow, are drastically reduced, as is artificial light pollution caused by high and low pressure sodium vapor and mercury vapor lights. The result is a high contrast image that reveals the H-alpha line in all its glory.
- The Optolong Sulfur II 6.5nm Extra Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 672nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). Like all Optolong filters that are designated as CCD, this SII filter also blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.
- The Optolong Oxygen III 6.5nm Extra Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 500nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). Like all Optolong filters that are designated as CCD, this OIII also blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.
- The Optolong 6.5nm SII filter can be used in conjunction with H-Alpha and OIII filters for false color emission line images like the Hubble Space Telescope.
- Please Note: This h-alpha filter is NOT for use on the Sun. To do so could cause irreparable eye damage or blindness. Don't even think about it!
- OPTOLONG 1.25 inch H-Alpha 7nm Filter
- OPTOLONG 1.25 inch SII 6.5nm Filter
- OPTOLONG 1.25 inch OIII 6.5nm Filter
- Three Sturdy Plastic Cases