The Optolong L1 Dual-Combo Set 2" (Optolong, SKU: L1-Dual-Combo) includes two filters: the L-Quad Enhance and the L-Para. The set is designed as a combination of broadband and narrowband filtration, enabling RGB signal capture together with H-alpha and O-III emission data while preserving accurate color balance.

Key features

• set of two filters: L-Quad Enhance and L-Para
• “broadband + narrowband” synergy for combining RGB data with H-alpha and O-III signals
• improved color balance with enhanced resistance to light pollution
• increased detail rendition in nebular and deep-sky structures

Main use and performance

• L-Quad Enhance: quad bandpass broadband filter for capturing RGB signals from continuous spectrum objects such as nebulae, galaxies and star clusters
• L-Para: dual narrowband 10 nm filter for H-alpha and O-III emission lines
• H-alpha and O-III transmittance exceeding 85% in optical systems with focal ratios of F2 and slower
• compatible with fast optical systems (F2, F2.8, F3.2, F4) as well as standard focal ratio telescopes
• enables post-processing workflows combining RGB with H-alpha and O-III data

Technical specifications

• set contents: 1 × L-Quad Enhance filter, 1 × L-Para filter
• L-Quad Enhance: quad bandpass broadband filter
• L-Para: dual narrowband 10 nm filter (H-alpha and O-III)
• multi-layer anti-reflection coatings
• ion-assisted deposition coating technology ensuring durability, scratch resistance and CWL stability independent of temperature changes
• planetary rotation system ensuring coating homogeneity, high pass-band transmission and high off-band optical density
• filter size: 2" (M48 × 0.75)