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.
1. L-eXtreme F/2 Introduction
Optolong L-eXtreme F/2 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.
♦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 systems, like RASA, Hyperstar, and other fast focal ratio telescope users;
♦Recommended for using a fast optical system with a 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 F/2 can effectively block light pollution so that the images will not affected by unwanted lights and skylight of the background. You can quickly get satisfactory pictures in fast optical systems.
2. Spectrum and Characteristic
Based on the characteristics of celestial bodies’ emission lines and light pollution emission lines, the L-eXtreme F/2 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.
How to read the chart?
▲The horizontal axis is the Wavelength in Nanometers(nm).
▲The vertical axis is transmission in %.
3. 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.