Optolong L-Quad Enhance Filter 2"

The Optolong L-Quad Enhance is a four band selective transmission filter engineered for advanced astrophotography in moderate to heavily light polluted skies. It simultaneously passes four critical nebular emission wavelengths, giving you stunning contrast and fine detail while preserving star sharpness. This makes it an ideal filter for emission nebula imaging using one shot color cameras, CMOS systems and DSLR setups.
 
Unlike traditional broadband solutions, the L Quad Enhance blocks large portions of city glow while letting essential nebula light through, resulting in clean backgrounds with excellent signal to noise ratio. It is especially effective for imaging rich nebula structures such as the Lagoon, Trifid, Heart, Soul, Rosette and North America regions.
 
Emission Lines Transmitted by the L-Quad Enhance
Hydrogen Beta at 486 nm
Oxygen III at 495.9 and 500.7 nm
Hydrogen Alpha at 656.3 nm
Sulfur II at 672 nm
 
These four wavelengths cover almost the entire meaningful emission range from large bright nebulae, making this filter incredibly versatile.
 
Optical Specifications
Substrate: High grade B270 optical glass
Thickness: 1.85 mm
Peak transmission: Above 90 percent at all passed wavelengths
Blocking range: 300 to 1000 nm
Blocking depth: Above 99 percent of unwanted light pollution lines
Surface quality: 60 to 40
Transmitted wavefront RMS: Lambda by 4
Parallelism: 30 seconds
 
Performance and Compatibility
Suitable for refractors, SCTs and Newtonian systems
Works efficiently with fast and slow telescope optics from f2 to f10
Designed for OSC, DSLR, cooled CMOS and mirrorless astrophotography
Helps shorten exposure times while retaining strong nebular detail
Minimal haloing due to precision multi-layer coatings

The Optolong L Quad Enhance gives you narrowband performance using a color camera setup, making it one of the most effective upgrade filters for deep sky imaging in urban environments.