Optolong Venus U 1.25″ Mounted Filter

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.

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