Optolong L-Synergy Dual Narrowband SII & OIII 7nm Filter – 2" Mounted
The SII/OIII filter that brings Hubble Palette imaging to your color camera.
The L-Synergy is Optolong's newest narrowband filter, introduced in 2025, and it solves a problem that color camera astrophotographers have faced for years: getting true SHO-style images without going monochrome. By isolating SII (672.4nm) and OIII (500.7nm) at a tight 7nm bandwidth, it works as the perfect companion to a standard Ha+OIII dual-band filter — together, you have all three emission lines needed for a Hubble Palette image, using color cameras throughout.
Even on its own, the L-Synergy is an excellent filter for sulfur and oxygen emission nebulae in light-polluted skies, delivering dark backgrounds, strong contrast, and a noticeably improved signal-to-noise ratio compared to broadband shooting.
Key Features
SII + OIII Dual Narrowband at 7nm FWHM — Precisely isolates the two emission lines at 672.4nm and 500.7nm, blocking virtually all light pollution, artificial lighting, and unwanted sky glow in between.
Designed for Color Cameras — Fully compatible with DSLR, color CMOS, and CCD cameras. No monochrome camera or filter wheel required for SHO-palette imaging.
Hubble Palette Imaging with a Two-Filter Setup — Pair the L-Synergy (SII+OIII) with any Ha+OIII dual-band filter to capture all three SHO emission channels with a color sensor.
Light Pollution Rejection — Selectively transmits nebula emission while blocking the full spectrum of common urban and suburban light pollution sources, including sodium, mercury, and LED streetlighting.
Halo-Minimized Optical Design — Optolong's updated optical design reduces bright star halos, a common issue with dual-band filters at fast focal ratios.
Ion-Assisted Deposition Coating — Multi-layer, non-cementing coatings applied using a planetary rotation system for exceptional uniformity, durability, and thermal stability. The central wavelength does not shift with temperature changes.
Specifications
| Filter Type | Dual Narrowband (SII + OIII) |
| Bandwidth (FWHM) | 7nm |
| SII Passband | 672.4nm |
| OIII Passband | 500.7nm |
| Size | 2" (M48×0.75 thread) |
| Suitable for | DSLR, Color CMOS, CCD |
| Coating | Ion-assisted multi-layer deposition |
| Substrate | Optical glass, non-cementing |
Who Is This Filter For?
The L-Synergy is aimed at color camera users who want to produce SHO (Hubble Palette) narrowband images without investing in a monochrome camera. If you already shoot Ha+OIII with a dual-band filter, adding the L-Synergy gives you the SII data needed to complete the trifecta. It's also a strong standalone filter for imaging oxygen and sulfur-rich objects like the Veil Nebula, Crescent Nebula, or WR134 — targets where OIII and SII signal tells a different story than hydrogen-alpha alone.
In the Box
- Optolong L-Synergy 2" mounted filter
- Protective case (PP plastic box with EVA foam lining)