The Optolong SHO narrowband filter set is designed for use with astronomical monochrome CCD, CMOS and DSLR cameras. These filters set are commonly used by astrophotographers to present their photos in Hubble Palette. This filter set includes H-Alpha 7nm, SII 6.5nm and OIII 6.5nm, covering the emission lines of 656.3nm, 671.6nma and 500.7nm respectively.  The filters provide high transmittance in order to obtain the maximum contrast of nebulae while cutting out background emission and suppressing bright starlight.

• Fine-optically polishing for double-sides—— Ensure accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces
• Ultrasonic wave cleaning substrate with purified water to remove impurities and dust effectively
• IRO source assisted coating - For durability and resistance to scratching, as well as stability on CWL (central wavelength).  No deviation from temperature change.
• Constant stringent quality testing processes - Each filter is tested by spectrophotometer and laser interferometer testing spectrum and wavefront to ensure market filter is qualified product
• Optolong will spare no effort to serve our customer with outstanding quality products and best service!