Chroma OIII filter 5nm - 2″ mounted

5nm OIII filter from Chroma Technology

Visit 5nm OIII filter from Chroma Technology is a narrow-band filter designed for astronomical imaging. It is optimized to capture the emission line of doubly ionized oxygen (OIII) at 500.7 nm, one of the most important emissions after H-alpha in nebula imaging. This filter is ideal for astrophotographers seeking high contrast and effective suppression of unwanted wavelengths.

Key features

• Bandwidth : 5 nm, offering precise isolation of the OIII line while blocking parasitic emissions (sodium lamps, mercury, etc.).
• High transmission : Up to 95 % at 500.7 nm, guaranteeing an excellent signal-to-noise ratio.
• Optical quality :
  • Surface polished to an accuracy of λ/4.
  • Multi-layer anti-reflective coatings on both sides to minimize halos and stray reflections.
• Available formats :
  • Mounted: 1.25", 2".
  • Unmounted: Customized formats (31 mm, 36 mm).
• Substrate thickness : Approx. 3 mm, made from a unique optical glass substrate for exceptional durability.
• Fragrance: Compatible with all other Chroma filters (except LoGlow), facilitating their use in filter wheels.

Applications

• Imaging OIII-rich nebulae :
  • Ideal for capturing objects such as the Veil Nebula, Orion Nebula and Rosette Nebula.
• Reducing light pollution :
  • Effectively blocks unwanted wavelengths, even in urban or suburban environments.
• Advanced astrophotography :
  • The perfect complement to H-alpha and SII filters for scientific palette images (SHO or Hubble palette).
• Compatibility with high-speed systems :
  • Works perfectly with focal ratios up to f/4.0.
  • An optimized version is available for high-speed systems (f/2.6 to f/3.6) to compensate for blueshift.

Technical highlights

• Exceptional durability :
  • Sputter coatings guarantee long-term spectral stability.
  • Resistant to extreme variations in temperature and humidity.
• Anti-halos design : Anti-reflective coatings eliminate halos around bright stars, delivering sharp, detailed images.
• Universal compatibility : Fits most filter wheels and drawers on the market.

Conclusion

The filter Chroma OIII 5nm is an indispensable tool for deep-sky imaging. Its optical precision, high transmission and ability to effectively reduce light pollution make it an essential choice for capturing the subtle details of nebulae rich in ionized oxygen (OIII).