The Optolong L-Synergy filter is specifically designed for use with color astronomical cameras and DSLR cameras. Essentially, it combines two narrowband filters: it features a 7 nm bandwidth optimized for the SII wavelength range (672.4 nm), as well as another for the OIII range (500.7 nm). Most diffuse nebulae are "brightest" in these ranges. The two narrow transmission bands filter out light pollution and disturbing moonlight, thereby uniquely effectively reducing background light for urban astrophotographers.
By using the dual application of the H-alpha and OIII (L-eXtreme) + SII and OIII (L-Synergy) filters, the limitations of narrowband astrophotography with color cameras can be overcome. With the L-Synergy, users can create deep-sky images in the Hubble palette style, similar to those captured with monochrome SHO (SII/Ha/OIII) systems—without having to switch to a monochrome camera or purchase additional SHO filters.
The filter has a narrow design, being only 5 mm thick (without thread). It is made from high-quality Schott glass, with multi-layer anti-reflection coatings vapor-deposited on its surface. The manufacturer recommends its use for systems with a focal ratio "slower" than f/3.3.
