Optolong 1.25" Filter Set with H-Alpha, SII, and OIII Filters

The Optolong 1.25" Filter Set is a premium triad of narrowband filters designed for serious deep-sky imaging in light-polluted skies. This set includes three critical emission line filters: H-Alpha (7nm), SII (6.5nm), and OIII (6.5nm), all optimized for CCD and DSLR astrophotography.

Each filter isolates a specific wavelength—656nm (H-Alpha), 672nm (SII), and 500nm (OIII)—to maximize contrast and reveal fine structural detail in nebulae. With tight FWHM bandpasses, these filters suppress unwanted skyglow and artificial light, enhancing signal-to-noise ratio in narrowband captures.

Crafted from Schott B260 optical glass and built in CNC-machined, ultra-thin anodized housings, these filters ensure minimal optical distortion and maximum clarity. Whether you're simulating the Hubble palette or capturing individual emission structures, this 3-piece set is a cornerstone for any serious narrowband imager.

• Filter Type: Narrowband Imaging Set
• Included Filters: H-Alpha (7nm), SII (6.5nm), OIII (6.5nm)
• Wavelength Centers: H-Alpha 656nm, SII 672nm, OIII 500nm
• Infrared Block: Yes (700–1100nm)
• Transmission: ≥80% at central wavelengths
• Filter Size: 1.25" (31.75mm)
• Clear Aperture: 26mm
• Substrate: Schott B260 optical glass (2.0mm thick)
• Surface Accuracy: λ/4
• Parallelism: <30 arcseconds
• Surface Quality: 60/40 per MIL-O-13830
• Coating Method: Electron-beam with Ion-Assisted Deposition
• Mount: CNC Machined, Black Anodized Aluminum Cells
• Cell Features: Laser-engraved, Ultra-thin Profile
• RoHS Certified: Yes

• Optolong 1.25" 7nm H-Alpha Filter
• Optolong 1.25" 6.5nm SII Filter
• Optolong 1.25" 6.5nm OIII Filter
• Protective Filter Case