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Optolong L-Ultimate Filter

RM 988.00

Optolong L-Ultimate Filter

L-Ultimate 3nm dual band designed to drastically reduce effect of light pollution, 3nm isolates nebulae's emissions into H-Alpha (red) and OIII (green-blue). It blocks light pollution, maximizes the signal from nebulae, and darkens the sky background. It also blocks artificial light from mercury vapor lamps, high and low pressure sodium vapor lights, and unwanted natural light caused by emission of neutral oxygen in atmosphere. Maximizes transmission of main emission lines of nebula in OIII (496nm and 500nm) and H-alpha (656nm). Used with DSLR, color/MONO CMOS and CCD, however, this filter is not suitable for fast ratio systems.

Advantage of L-Ultimate is that it only passes emission lines OIII(500.7nm) and Ha(656.3nm), in which case all other light pollution emission lines are eliminated so that only emission and reflection signals of nebula are captured during imaging. Therefore, sky background of the image is darker, and the contrast between the nebulae and the signal-to-noise ratio are improved to the greatest extent. In heavy light pollution areas, product can also selectively filter light pollution and clutter signals through emission lines of nebulae, and finally avoid the impact of light pollution on astrophotography.

It is different from series of dual-narrowband L-eNhance and L-eXtreme in that L-Ultimate is dual-3nm bandwidth filter that only passes through Ha and OIII emission lines. You will get darker sky background, more contrast of image and suppression on stars. L-Ultimate has also been optimized in terms of halo performance, so that there is no obvious halo when shooting on a bright star object.



Sbustrateoptical glass
FWHMOIII 3nm Ha 3nm
Blocking range300-1000nm
Surface quality60/40
Transmitted Wavefront RMS:λ/4





Reference Spectrum


※This curve is only for reference, and is not used as the final product data.





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.

Contact 011-11230602 For More Information. Available In Stock, 100% Original Local Unit With Full Warranty And Aftersales Service