Optolong L-Ultimate 2" dual-3nm filter

Optolong L-Ultimate Dual 3nm Narrowband Filter - 2" for Astrophotography

Designed for astrophotographers aiming to capture breathtaking images of emission nebulae in areas with high light pollution, the Optolong L-Ultimate Dual 3nm Narrowband Filter - 2" is an essential accessory. This high-performance dual-band filter is crafted to enhance the capabilities of digital SLRs and monochrome cameras even in challenging lighting conditions.

The Optolong L-Ultimate filter excels with a remarkable transmission rate of over 90% for the spectral lines of ionized hydrogen (Hα) and oxygen (OIII) atoms. By effectively blocking unwanted spectral lines from sodium and mercury lamps, this filter allows photographers to produce sharp, high-contrast images, even in urban settings or under a bright moon. Its narrow bandpass of just 3 nm ensures superior contrast and a darker background, surpassing other two-band filters like the L-eNhance and L-eXtreme.

To boost its optical performance, the Optolong L-Ultimate filter is equipped with a full multi-layer anti-reflection coating, applied using state-of-the-art ion implantation techniques. This technology not only optimizes optical quality but also enhances durability, offering excellent resistance to scratches.

Note: This filter is not recommended for use with optical tubes that have extremely high light shades.

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

• High transmission dual-band filter optimized for Hα and OIII lines.
• Narrow 3 nm half-width transmission bands for enhanced contrast.
• Exceptionally effective at reducing light pollution.
• Minimized 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 is backed by a 24-month warranty, offering peace of mind to astrophotography enthusiasts.