Optolong L-Ultimate 1.25" Light Pollution Dual Band Filter

The Optolong L-Ultimate 1.25" Light Pollution Dual Band Filter is engineered for deep space astrophotography with color and monochrome cameras. Featuring ultra-narrow 3 nm transmission bands centered on H-alpha (656.3 nm) and OIII (500.7 nm), this filter is designed to suppress nearly all unwanted light, allowing you to capture high-contrast images even in heavily light-polluted environments.

Ideal for emission nebulae, this filter provides enhanced signal-to-noise ratio and eliminates nearly all haloing—even around bright stars like 52 Cyg. It is a significant upgrade over broader dual-band filters, giving you sharper, more vivid images with improved detail in both H-alpha and OIII emission regions. Its durable construction and premium coatings ensure long-term performance and optical precision.

• Filter Type: Dual Narrowband (Light Pollution Reduction)
• Size: 31.75mm (1.25")
• Filter Shape: Round
• Insert Style: Threaded
• Transmission Wavelengths:
  • OIII: 500.7 nm ± 1.5 nm (3 nm bandwidth)
  • H-alpha: 656.3 nm ± 1.5 nm (3 nm bandwidth)
• Optical Thickness: 1.85 mm
• Compatibility: DSLR, CMOS, and CCD cameras
• Minimum Focal Ratio: f/4 or slower
• Halo Suppression: Yes (tested on 52 Cygni)
• Material: High-quality coated optical glass
• Use Case: Imaging emission nebulae in urban skies

• Optolong L-Ultimate 1.25" Light Pollution Dual Band Filter
• Plastic Storage Case