Optolong Venus U Filter 1.25" Mounted

Article number: 12601
Availability: Order Now!
Delivery time: Ships from our west coast warehouse in 7-10 days

Image the sulphuric acid clouds of Venus or do UV landscape photography with the Optolong 1.25” Venus U Filter. This special filter can only be used for imaging through CCD/CMOS or DSLR cameras* since our eyes are not sensitive to UV light. The Venus U filter passes UV-A light at 320nm to 400nm with a peak transmission of 80%, and blocks 200nm to 280nm as well as everything above 400nm, which include the visible and infrared spectral regions.

*In order to use this filter with a monochrome CCD or DSLR camera, you will need to remove anything that keeps UV light from reaching the sensor. For CCD/CMOS cameras, this would include the sensor’s cover glass and internal UV-IR blocker, and for DSLR’s, the built-in low pass filter would need to be removed. A special UV lens may be required, since some lenses have anti-reflective coatings that block all light below 380nm. Investigate your gear’s specifications to decide what is best for your applications.

The Optolong 1.25” Venus U 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. Each filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted, black anodized, and then laser engraved. The result is a super thin filter cell that will produce a clear aperture of 26mm.

Quality Filter Materials:

  • Schott B260 substrate material from Germany, 2.0mm thick
  • CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture; Laser-engraved to prevent fading
  • 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
  • 80% maximum transmission at spectral region 320-370nm
  • Precision off-band blocking on ultraviolet wavelength 200-280nm, visible and infrared spectral region
  • 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
  • Thin metal cells have a clear aperture of 26mm for 1.25” filters
  • Each filter comes with a plastic case with high pressure EVA case lining
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