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Optolong L-Quad Enhance Quad-Bandpass (L-QEF) Imaging Filter

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Optolong L-Quad Enhance Filter (L-QEF) Quad Bandpass Light Pollution Suppression Filter

The Optolong L-Quad cuts out light pollution from mercury and sodium lamps and produces a nice broadband image with minimal colour cast. This filter is a broadband filter that suppresses light pollution wavelengths. It is good for star clusters, dark and reflection nebulae, and galaxies from light-polluted skies.

L-Quad Enhance Filter (L-QEF) is a quad bandpass light pollution suppression filter for colour cameras. It effectively suppresses the transmission of light pollution wavelengths, especially light pollution generated by artificial lighting (including mercury and sodium lamps), as well as the effects of natural skylight-induced effects on the shot, thus effectively enhancing the contrast and details of the celestial bodies, and making the objects more distinct and stereoscopic. This filter provides better colour balance while improving resistance of light pollution. The L-Quad can be used for both wide field astrophotography, such as the Milky Way in Summer and Winter, and deep sky objects such as nebulae, galaxies, star clusters, and so forth; It allows you to save a lot of time during the shooting process and get better results at the same time. The design of quad bandpass maximises the colour balance of nebulae, galaxies and other broadband spectral targets.

Key Features:

  • Cuts out light pollution from mercury and sodium lamps and produces a nice broadband image with minimal colour cast;
  • Signal-to-noise ratio (SNR);
  • Near IR cut-off to 1000nm, reducing the effects of IR noise;
  • L-QEF has more than 90% transmittance of the nebula emission lines at H-Beta/OIII/H-Alpha/SII, with cut-off depth from OD2 to OD4, thus providing a significant increase in resistance to light pollution. L-QEF is good for night sky from Bortle 1 to Bortle 7 levels; (Bortle 8, Bortle 9 environments shall not be recommended, kindly chose Optolong other narrow-band filters, 3nm, 7nm type of filters are available.);
  • Suitable for wide range of deep sky targets: it covers most nebulae, galaxies, star clusters, reflected and emitted line signals astronomical objects with higher contrast and rich details while maintaining excellent colour balance. L-QEF is superior to other filters of the same type.

Based on the characteristics of celestial bodies’ emission lines and light pollution emission lines, L-Quad Enhance filter effectively reduces the impact of light pollution and suppresses the background light of astronomical objects, thus effectively enhancing the contrast and details of the celestial bodies. Using L-QEF filter can help you save a lot of time during the shooting process, yet obtaining incredible results.

 Optolong L-Quad Enhance Filter (L-QEF) Transmission Graph

Major emission wavelengths of nebulae:

  • H-a: 656.3nm
  • H-b: 486.1nm
  • OIII: 495.9nm, 500.7nm

Major emission wavelengths of artificial light pollution:

  • Hg: 435.8nm, 546.1nm, 577nm, 578.1nm
  • Na: 598nm, 589.6nm, 615.4nm, 616.1nm

Specifications: Optolong L-Quad Enhance Quad-Bandpass (L-QEF) Imaging Filter

Substrate Optical glass
Thickness 1.85mm

Quad bandpass filter

Blocking range 300-1000nm
Blocking depth OD2-OD4
Surface quality 60/40
Transmitted Wavefront RMS λ/4
 Parallelism 30s

What's in the Box

What's in the Box: Optolong L-Quad Enhance Quad-Bandpass (L-QEF) Imaging Filter

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