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Optolong UV-IR Cut Filter - 31mm Unmounted - UVIR-31U

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Optolong UV-IR Cut Filter - 31mm Unmounted

Improve image sharpness with the addition of an Optolong UV-IR Cut Filter, which blocks Ultraviolet and Infrared transmissions but lets the visible spectral region shine through. The IR (700nm to 1100nm) and UV (300nm - 400nm) part of the spectrum are invisible to human eyes, but not to most CCD and other digital cameras, which are sensitive to 300nm to 1100nm. With the Optolong UV-IR Cut filter installed, violet halos and an overall soft image are a thing of the past. This filter also reflects heat radiation and provides great protection against dust.

The Optolong 31mm Unmounted UV-IR Cut Filter is made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength, or CWL. This UV-IR Cut filter is designed to be used with color filter wheels that accept 31mm unmounted filters.

Quality Filter Materials:

  • Schott B260 substrate material from Germany, 2.0mm thick
  • Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition

Optolong Filter Manufacturing Processes and Parameters

  • Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
  • Surface quality, according to MIL-O-13830, is 60/40
  • 95% transmission at visible spectral region 420-680nm highly passing the major nebula emission lines of H-Alpha 656nm, SII 672nm and NII 654nm and 658nm
  • Ultraviolet 300-400nm and infrared wavelength 700-1100nm cut-off
  • Optolong’s planetary rotation system is a homogenous and precise coating procedure that ensures both high transmission of pass-band and optical density of off-band
  • Each filter comes with a plastic case with high pressure EVA case lining

About Optolong

Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.