Optolong L-eXtreme F2 Fast Optics Dual Narrowband

Optolong L-eXtreme F2 is a dual-band (500.7 nm and 656.28 nm, FWHM=7 nm) narrowband pass filter that meets the requirements for transmission at continuously varying angles. Astronomically characterised spectral lines (OIII, Ha) as the main transmission wavelengths, the OIII and H-Alpha nebula emission lines pass accurately at f2 - f3.3 Focal Ratio. It's a product that Optolong has developed specifically for fast optical systems, or fast focal ratio imaging systems. It has performed well on RASA, HyperStar and other fast ratio telescopes.

Key Features:

• Together with one-shot colour astronomical cameras, monochrome astronomical cameras, and Digital SLR cameras, you can fast and quickly obtain clear and detailed images of the deep sky;
• Ideal for fast optical system, like RASA, Hyperstar and other fast focal ratio telescope users;
• Recommended for using fast optical system with focal ratio from f2 to f3.3;
• Anti-light pollution、better contrast、more details of the celestial bodies:This filter cuts out background light and noise beyond the target celestial bodies to get better details and contrast of the images. L-eXtreme F2 can effectively block light pollution so that the images will not affected by unwanted lights, and sky light of the background. You can quickly get satisfactory pictures in fast optical systems.

Spectrum and Characteristic

Based on the characteristics of celestial bodies’ emission lines and light pollution emission lines, the L-eXtreme F2 retains the prominent nebula OIII and Ha colours while blocking most of the light pollution. Specifically designed and optimally calculated for the characteristics of a fast optical system, the L-eXtreme F2 always keeps both OIII and Ha bands having high transmittance, which helps users to capture nebulae emission lines in these bands more accurately and quickly, and obtain better astrophotographic images.

Coating Technology

• Multi-layers anti-reflection coating
• Non-cementing optical substrate coating
• Optolong filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.
• Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.