Optolong L-Quad Enhance Filter

The Optolong L-Quad Enhance Filter cuts out light pollution from mercury and sodium lamps and produces a nice broadband image with minimal color cast as it performs well for good for star clusters, dark and reflection nebulae, and galaxies from light-polluted skies.

Optolong L-Quad Enhance FilterIn addition to suppressing the transmission of light pollution wavelengths such as light pollution generated by artificial lighting, the Optolong L-Quad Enhance Filter suppresses the effects of natural skylight-induced effects on astroimaging, thus effectively enhancing the contrast and details of the celestial bodies and making the objects more distinct and stereoscopic.

The filter can be used for wide field astrophotography, such as the Milky Way, and deep sky objects such as nebulae, galaxies, star clusters. The quad bandpass design maximizes the color balance of nebulae, galaxies and other broadband spectral targets.

The Optolong L-Quad Enhance Filter 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. Also, with a near IR cut-off to 1000nm, IR noise is greatly diminished. The filter works best for night skies in the Bortel 1 to Bortel 7 range.

Optolong uses specialized coatings to protect the quad-band filter from scuffs, scratches and to improve its sturdiness. Utilizing Ion-assisted deposition coating technology, the filter provides stability on the wavelengths captured when exposed to changes in temperatures, such as can be experienced throughout a night of imaging. The Optolong L-Quad Enhance Filter also contains multiple layers of anti-reflective coating, ensuring the images captured remain pristine.

The Optolong L-Quad Enhance Filter specifications include:

– Substrate: Optical glass

– Thickness: 1.85mm

– FWHM: Quad bandpass filter

– Blocking range: 300-1000nm

– Blocking Depth: OD2-OD4

– Surface quality: 60/40

– Transmitted Wavefront RMS: λ/4

– Parallelism: 30s

You can learn more about the Optolong L-Quad Enhance Filter here.

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