Optolong L-Para filter

Optolong has introduced the L-Para (L-Parallels), a dual narrowband 10nm light pollution filter tailored to meet the demanding requirements of astrophotographers. With a full width at half maximum (FWHM) of 10nm for the OIII (500.7nm) and H-Alpha (656.3nm) emission lines, the filter achieves a transmittance exceeding 85% in systems with focal ratios of F2 and above. This high-performance filter effectively suppresses light pollution from mercury lamps, sodium lamps, and LEDs, while enhancing contrast and maintaining excellent anti-halo properties.

Optolong L-Para Flter (L-Parallels)

The L-Para filter is designed to deliver consistent results across various optical systems, including both fast optics like RASA and Hyperstar systems and standard telescopes. Its ability to maintain high transmission rates even with oblique light incidence ensures versatility and reliability. This makes the L-Para suitable for observing and imaging in diverse conditions, from urban environments with Bortle Scale 7 skies to darker rural areas.

Drawing inspiration from Chinese cultural symbolism, the design of the L-Para centers on the number ten, representing perfection and completeness. The dual 10nm bands emphasize this theme, encapsulating a wish for ideal astrophotographic experiences under clear skies.

Optolong L-Para Filter features

The L-Para filter incorporates several performance-driven features, ensuring it meets the needs of both amateur and professional astronomers:

• Broad Compatibility: The filter adapts seamlessly to both fast and standard optical systems, supporting focal ratios as low as F2. This universality allows users to employ a single filter across multiple setups without compromising performance.
• Light Pollution Suppression: By selectively cutting off emission lines from artificial light sources, the L-Para enhances the visibility of celestial objects even in light-polluted areas.
• High Transmission Efficiency: Its greater-than-85% transmittance of OIII and H-Alpha nebula emission lines ensures brighter and more detailed images.
• Enhanced Contrast: The deep cut-off of light pollution bands, combined with the high transmission of target emission lines, significantly improves image clarity and detail.
• Anti-Halo Optimization: Through extensive testing and refinements, the L-Para minimizes halos around bright stars, preserving the natural appearance of astrophotographs.
   

Optolong L-Para Filter spectrum and coating technology

The L-Para filter balances high transmission of OIII and H-Alpha lines while blocking light pollution emission lines. To achieve this, Optolong employs advanced coating technology, including multi-layer anti-reflection coatings and ion-assisted deposition. These coatings provide durability, resistance to scratches, and stability in maintaining the central wavelength (CWL) under temperature fluctuations. A planetary rotation system ensures uniformity in the coatings, resulting in precise optical density and consistent performance.

Optolong L-Para Filter pricing and availibility

The Optolong L-Para filter is available globally, with a unit price of $259 for the 2-inch mounted version. Packaging includes a silver outer box, a PP plastic inner box, and high-pressure white EVA lining to ensure the filter’s safety during storage and transport.

Optolong L-Para Filter review: Fast imaging and light pollution blocking

Teagan Grable from High Point Scientific recently reviewed the Optolong L-Para 2" dual band filter, highlighting its impressive performance and features for astrophotography. This new addition to Optolong’s series of dual narrow band filters offers a 10 nanometer band pass, which sets it apart from previous models such as the L-Enhance, L-Extreme, and L-Ultimate. Grable noted that the L-Para filter is designed for imaging systems with focal ratios as fast as f/2, making it a versatile option for a wide range of telescopes, from faster systems to slower ones, such as those with f/15 ratios.

Grable emphasized the filter’s capability to block light pollution caused by sodium and mercury lamps, which is crucial for achieving clearer images in urban environments. Additionally, the L-Para filter provides contrast similar to the L-Extreme filter while reducing the halo effect often seen around bright stars with other narrow band filters. This feature was particularly important during the review, as the L-Para filter demonstrated a soft glow around bright stars, such as Propus, during tests on the Jellyfish Nebula.

One of the standout aspects of the L-Para filter, according to Grable, is its ability to produce detailed and vibrant images even with just an hour of exposure time. During the test, Grable’s colleague, Diana, captured impressive results after just one hour of integration on her first night using the filter. The captured image of the Jellyfish Nebula displayed an exceptional amount of nebulosity, fine details, and vibrant colors. Grable highlighted that this rapid result demonstrated the L-Para’s potential for capturing deep-sky objects with high clarity and balance.

The filter’s performance was further validated when Diana continued her tests, collecting a total of six hours of exposure time. The final image showcased the filter’s ability to reveal significant amounts of OIII emission data, which contributed to a richly detailed and well-balanced representation of the nebula. Grable noted that the results were particularly impressive, with the L-Para filter revealing intricate structures and natural color tones in the nebula.

In conclusion, Grable’s review emphasized the Optolong L-Para filter’s versatility, especially in fast focal ratio systems, and its ability to capture high-quality images with minimal exposure time. With its strong light pollution blocking capabilities and ability to minimize haloing effects around bright stars, the L-Para filter offers astrophotographers a reliable tool for imaging deep-sky objects. The filter’s balance of contrast, clarity, and detail makes it a promising choice for future astrophotography projects. Grable and the High Point Scientific team look forward to testing the filter on faster imaging systems like the Celestron RASA and HyperStar in future reviews.