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Optolong UBVRI Filter Set - 31mm Unmounted - UBVRI-31U
Optolong UBVRI Filter Set - 31mm Unmounted
This photometric UBVRI filter set includes five 31mm unmounted filters: ultraviolet (U), blue (B), visual (V), red (R), and infrared (I).
The Optolong 31mm Unmounted UBVRI Filter Set 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 filter set is designed to be used in 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
- 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
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.