Optolong L-Extreme 2" dual band filter

The Optolong L-Extreme 2 "filter is an exceptional tool designed specifically for capturing stunning images of bright emission nebulae using digital SLRs and monochrome cameras, especially in areas with high light pollution.

This filter boasts an impressive transmission rate of over 90% for the spectral lines emitted by ionized hydrogen (Hα) and oxygen (OIII) atoms. With a narrow half-width of only 7 nm, the OIII line is effectively separated from Hβ. The filter's narrow half-width (FWHM) and efficient suppression of spectral lines produced by sodium and mercury lamps allow for the capture of sharp and high-contrast images, even in close proximity to densely populated cities. Additionally, the narrow bandwidth significantly enhances contrast during brightly moonlit nights or when photographing emission nebulae near intense stars.

To further enhance its optical performance, the filter is coated with a full multi-layer anti-reflection coating, utilizing advanced ion implantation techniques. This ensures not only exceptional optical quality but also remarkable durability and scratch resistance.

Key Features of the Optolong L-Extreme 2 "Filter:

Dual-band filter with high transmission for Hα and OIII lines.

Highly effective light pollution blocking (> 99% efficiency).

Scratch-resistant multi-layer anti-reflective coating.

Technical Specifications:

• Filter Type: Dual-band filter.
• Filter Diameter: 2 ".
• Half Bandwidth: 7 nm.
• Pass Bands: Hα, OIII.
• Maximum Transmission: > 90%.
• Blocking Range: 300 - 1000 nm.
• Light Pollution Blocking Efficiency: > 99%.
• Filter Material: Schott B 270 glass.
• Coating Type: Full multi-layer coating (FMC).
• Filter Thickness: 1.85 mm.
• Surface Quality Index: 60/40.
• Parallelism: 30 ".
• RMS Execution Accuracy: λ / 4.
• Frame Material: Aluminum.

Kit Components:

• Optolong L-Extreme 2 "Filter.

Warranty:

24 months.