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Optolong L-QEF Quad Enhance Filter 2"

7 unit/s in stock

US$ 214.46


Short Description

L-QEF eliminates light pollution caused by mercury and sodium lamps and produces a broadband image with minimal color cast. This filter is broadband and suppresses wavelengths of light pollution. It is great for star clusters, dark and reflection nebulae, as well as galaxies in skies affected by light pollution.


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The L-Quad Enhance Filter (L-QEF) is a quad bandpass filter designed to suppress light pollution in color cameras. Effectively suppresses the transmission of light pollution wavelengths, especially those generated by artificial light sources such as mercury and sodium lamps, as well as the effects of natural sky light on images, effectively enhancing the contrast and details of bodies celestial, making objects more distinct and stereoscopic. This filter ensures better color balance and further resistance to light pollution. L-QEF can be used both for wide-field astronomical photography, such as the Milky Way in summer and winter, and for deep-sky objects such as nebulae, galaxies, star clusters, and so on. It allows you to save time during the shooting process while achieving better results. The quad bandpass design maximizes the color balance of nebulae, galaxies and other broadband spectral targets.

Main features:

  • Eliminates light pollution caused by mercury and sodium lamps and produces a broadband image with minimal color cast;
  • Signal-to-noise ratio (SNR);
  • Cutoff in the near infrared up to 1000 nm, reducing the effects of infrared noise;
  • L-QEF has a transmission of over 90% of nebulae emission lines to H-Beta/OIII/H-Alpha/SII, with an absorbance ranging from OD2 to OD4, thus offering a significant increase in resistance to light pollution. L-QEF is suitable for night skies with levels from Bortle 1 to Bortle 7; (Not recommended for Bortle 8 or Bortle 9 environments, kindly recommend choosing other Optolong narrow-band filters, available in 3nm and 7nm thicknesses.);
  • Suitable for a wide range of deep sky lenses: Covers most nebulae, galaxies, star clusters and astronomical objects with reflected and emitted emission lines, offering greater contrast and richer detail while maintaining excellent image balance color. L-QEF is superior to other filters of the same type.

Spectrum and Characteristic


Sbustrateoptical glass

Quad bandpass filter

Blocking range300-1000nm
Blocking DepthOD2-OD4
Surface quality60/40
Transmitted Wavefront RMSλ/4

Additional Information

Additional Information

NameOptolong L-QEF Quad Enhance Filter 2"
Warranty2 Years
Diameter2" (50.8mm)