Optolong L-eXtreme Filter 2 inch

Optolong Filters L-eXtreme 2″ is an advanced narrowband filter designed specifically for astrophotography of emission nebulae with color cameras (OSC) and DSLRs. The filter allows only the emission lines H-alpha (656 nm) and OIII (500 nm) to pass through and blocks virtually all other light. This ensures extremely high contrasts and a darkened sky background, even in urban environments with strong light pollution.

The dual transmission makes this filter particularly suitable for cameras with a Bayer pattern, as both the red and green/blue channels are optimally utilized. As a result, nebulae such as the Veil Nebula, Orion Nebula and North American Nebula are captured with stunning clarity and detail. Compared to wider filters such as the L-eNhance, the L-eXtreme offers even more selectivity, which is ideal for astrophotography under difficult conditions, such as during moonlight nights.

The filter is made of high-quality optical glass with multiple anti-reflection coating and mounted in a robust 2″ aluminum mount. This larger size makes it compatible with widescreen astrophotography and telescopes with 2″ accessories, giving more flexibility when using wide-angle eyepieces and camera adapters.

Observation goals
This filter is ideal for astrophotographers who want to photograph emission nebulae with an OSC camera or DSLR, even from light-polluted areas. It supports long exposure times and stacking techniques, delivering results normally possible only under dark sky conditions. For visual use, the bandwidth is too narrow and therefore less suitable.

Specifications

• Type: Narrow-band filter (dual-band)
• Diameter: 2″ mount
• Transmittance: H-alpha (656 nm) and OIII (500 nm)
• Material: Optical glass with multiple coating
• Mount: Aluminum
• Application:
  • ✓ Astrophotography of emission nebulae
  • ✓ Suitable for OSC cameras and DSLRs
  • ✓ Works under heavy light pollution and moonlight
  • ✗ Not intended for visual use