Optolong L-eXtreme Filter

• Dual-band light pollution filter - 1.25-inch size.
• The L-eXtreme filter is dual-band that passes H-alpha and O-iii emission lines.
• It isolates these two nebula emission lines so that the contrast and signal-to-noise ratio between nebulae were maximized.
• These two elements (Hydrogen and Oxygen) factor greatly in the scientific exploration of life.

Introducing the Optolong L-eXtreme Filter:

The Optolong L-eXtreme Filter is a dual-bandpass filter designed to enhance astronomical observations with one-shot color cameras like DSLRs (digital SLR) and monochrome CCD cameras. This filter is particularly well-suited for fast optical systems and provides a cost-effective solution that enables amateur astronomers to capture rich emission nebulae, even in environments with significant light pollution. The L-eXtreme filter is engineered to maximize the contrast and signal-to-noise ratio of nebulae by isolating the H-Alpha and Oxygen III nebula emission lines.

L-eXtreme Introduction: The L-eXtreme filter, with its dual 7nm bandpass design, is compatible with one-shot color cameras and performs admirably with fast optical systems. It offers convenience and affordability, allowing amateur astronomers to capture stunning emission nebulae images, even in the presence of substantial light pollution. Optolong believes that the L-eXtreme filter represents an excellent choice for fast optical systems, offering competitive pricing. This filter selectively transmits the H-Alpha and Oxygen III nebula emission lines, effectively enhancing contrast and signal-to-noise ratio. It's a valuable tool for observers living in heavily light-polluted areas or during moonlit nights.

Key Difference from L-eNhance: Unlike the Optolong L-eNhance filter, which is a tri-band filter (transmitting H-beta, H-alpha, and OIII), the L-eXtreme filter is a dual-band filter that passes only the H-Alpha and OIII emission lines. This design has the advantage of zero transmission between the H-beta and OIII lines, as there are no nebula emission lines within that range. As a result, it effectively blocks out light pollution, maximizing the signal from nebulae and darkening the sky background during imaging. The L-eXtreme filter excels at isolating the emission lines, offering superior protection against light pollution.

Spectrum Characteristics:

• Substrate: B270
• Thickness: 1.85mm
• Peak Transmission (Tpeak): T>90%
• Blocking Range: 300-1000nm
• Blocking Depth: Light pollution line blocking >99%
• Surface Quality: 60/40
• Transmitted Wavefront RMS: λ/4
• Parallelism: 30 seconds

Coating Technology: The Optolong L-eXtreme Filter employs advanced coating technologies to ensure durability and optical performance, including multi-layer anti-reflection coating and non-cementing optical substrate coating. Precision coating based on Ion-assisted deposition coating technology is utilized to resist scratching and maintain stability in terms of the central wavelength (CWL) even under temperature variations. A planetary rotation system during the coating process guarantees precision and uniformity of coatings, resulting in high transmission in the pass-band and optimal optical density in the off-band.

Packaging: The filter is thoughtfully packaged for protection:

• Outer Box: Silver box
• Plastic Box: Made of PP material
• Lining: Features imported high-pressure white EVA material.

In summary, the Optolong L-eXtreme Filter is a valuable tool for amateur astrophotographers and astronomers, especially those facing light pollution challenges. Strict adherence to safety guidelines is crucial, particularly when it comes to solar observations, to avoid potential eye damage.

Interpreting the Chart: The provided chart offers insights into the filter's performance characteristics:

• The horizontal axis represents the wavelength in nanometers (nm).
• The vertical axis illustrates transmission percentages (%).
• The RED line represents the H-Alpha line, while the GREEN line represents the OIII emission line. Artificial emission lines are depicted in ORANGE.