Binorum CLS (City Light Suppression) Filter – Your Gateway to Deep-Sky Objects from the City
The Binorum CLS filter is designed for observing nebulae, deep-sky objects, and astrophotography. This broadband frequency filter blocks city light sources and is especially effective for telescopes with small apertures.
Why This Is One of the Most Valuable Filters for Small Telescopes
If you own a telescope with an aperture of 60-150mm and live in or near a city, the CLS filter is one of the most useful accessories you can buy. While many filters require large apertures to show their full potential, the CLS filter works brilliantly even with modest telescopes, making deep-sky objects visible that would otherwise be lost in light pollution.
How It Works
The CLS filter is optimized for visual observation and photographing deep-sky objects in urban environments. Artificial background light is almost completely blocked, while stars and nebulae retain their brightness. The result is dramatically increased contrast.
The filter's effect is similar to a UHC filter, but the CLS has a broader spectrum of transmission, making it more versatile and particularly suitable for small telescopes with apertures starting from 60mm.
The Urban Astronomer's Solution
When observing in urban and suburban areas, light pollution from street lighting and advertising severely interferes with viewing deep-sky objects (DSO). The Binorum CLS is a type of broadband filter specifically designed to suppress urban light pollution. It blocks scattered light from street lamps while allowing the rest of the spectrum to pass through.
The Binorum CLS filter darkens the sky background, making nebulae stand out and significantly increasing image contrast. The CLS is used for both visual observation and astrophotography and is compatible with all telescope models with a standard 1.25" eyepiece fitting.
Perfect for Beginners and Small Telescopes
This is the filter we most often recommend to city-based astronomers with entry-level telescopes. Unlike narrowband filters that require large apertures and dark skies to show their benefits, the CLS filter delivers immediate, obvious improvements even with a 60mm or 70mm refractor under heavily light-polluted skies.
Transform your urban observing experience – see nebulae, galaxies, and star clusters that seemed impossible from your location. The CLS filter proves that you don't need to drive hours to dark skies to enjoy deep-sky astronomy.
Technical Specifications
- Type: Broadband light pollution filter
- Fitting: Standard 1.25" threaded
- Minimum recommended aperture: 60mm
- Use: Visual observation and astrophotography
- Best for: Emission nebulae, planetary nebulae, some galaxies and star clusters
- Compatible with: All telescopes with 1.25" eyepiece holders
Essential filter for urban astronomy • Proven performance with small apertures • Immediate contrast improvement • Works for visual and photographic use
