Optolong L-Pro 2” filter

Optolong Filters L-Pro 2” is a broadband light pollution filter designed for astrophotography as well as visual observation in areas with moderate to strong light pollution. Its multiband transmittance preserves the natural colors of deep-sky objects, unlike traditional UHC or CLS filters that often give an unnatural color balance. This makes the L-Pro particularly suitable for DSLRs, One-Shot-Color cameras with CMOS sensors (such as ZWO) and even for luminance shots with MONO cameras.

The filter allows important emission lines (H-alpha, H-beta, O-III, N-II and S-II) to pass virtually unobstructed, while suppressing interfering wavelength lines from artificial lighting, such as sodium and mercury lamps, as well as natural “skyglow” from oxygen in the atmosphere. This significantly increases contrast and effectively darkens the sky background. In photography, exposure times up to three times longer than without a filter are possible, leading to deeper range and more detail in nebulae and galaxies.

The filter is constructed of high-quality Schott glass and coated with an extremely durable IBAD (ion-beam assisted deposition) coating. This process guarantees scratch resistance, color stability and high transmission even with temperature fluctuations.

Observation goals
The Optolong Filters L-Pro 2” filter is the ideal choice for astrophotographers working in light-polluted environments who want to maintain natural color balance. Suitable for DSLR, CMOS and MONO cameras, it can also be used for visual observations with large telescopes. Expect a marked improvement in objects such as emission nebulae, reflection nebulae, galaxies and globular clusters. The filter is not suitable as a solar filter.

Specifications

• Type: Broadband multiband light pollution filter
• Barrel size: 2”
• Material: shot glass
• Transmitted spectral lines: H-alpha, H-beta, O-III, N-II, S-II
• Transmission: approx. 95%
• Coating: electron beam evaporation + IBAD, scratch resistant
• Surface accuracy: 1/4 λ
• Width: 1.85 mm
• Use: Astrophotography (DSLR, CMOS, MONO), visual use