Optolong L-Ultimate 2" dual-3nm filter

For astrophotography enthusiasts seeking to capture stunning images of emission nebulae amidst high light pollution, the Optolong L-Ultimate 2" filter is an invaluable tool. This dual-band filter is designed to optimize the performance of digital SLRs and monochrome cameras under challenging conditions.

The Optolong L-Ultimate filter boasts an impressive transmission rate of over 90% for the spectral lines emitted by ionized hydrogen (Hα) and oxygen (OIII) atoms. By efficiently blocking out spectral lines associated with sodium and mercury lamps, this filter enables photographers to achieve sharp and contrasting images even when shooting near heavily populated areas or during brightly moonlit nights. Notably, the filter's narrow half-width of only 3 nm ensures enhanced contrast and a darker background compared to its two-band counterparts, the L-eNhance and L-eXtreme filters.

To further elevate its optical performance, the Optolong L-Ultimate filter features a full multi-layer anti-reflection coating applied using advanced ion implantation techniques. This cutting-edge coating not only maximizes optical perfection but also enhances durability, making it highly resistant to scratches.

Please note that the Optolong L-Ultimate 2" filter is not suitable for use with optical tubes that possess the highest light shades.

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

High transmission dual-band filter optimized for Hα and OIII lines.

Narrow half-width transmission bands of 3 nm for improved contrast.

Highly effective in cutting out light pollution.

Reduced halo effect when capturing bright stars.

Scratch-resistant multi-layer anti-reflection coating.

Technical Specifications:

• Filter Type: Dual-band filter
• Filter Diameter: 2"
• Half Bandwidth (FWHM): 3 nm
• Pass Bands: Hα, OIII
• Maximum Transmission: ~90%
• Blocking Range: 300 - 1000 nm
• Equivalent Optical Density for Blocking Range: > OD4
• Coating Type: Full Multilayer Coating (FMC)
• Substrate Material: Optical Glass
• Surface Quality Index: 60/40
• Parallelism: 30"
• RMS Execution Accuracy: λ/4

Included Components:

• Optolong L-Ultimate 2" Filter

Warranty:

The Optolong L-Ultimate 2" Filter comes with a 24-month warranty, providing peace of mind to astrophotography enthusiasts.