A. About Optolong's UV-IR Cut FIlter

Optolong's UV-IR cut filter is designed to block ultraviolet /*C*and*C*/ infrared wavelengths to improve sharpness of the image as most of the optics are designed for the visible spectrum, because it's very difficult to /*C*create*C*/ a lens with the same focal point for the visible /*C*and*C*/ IR spectrum. It is used on a digital camera /*C*and*C*/ the video, which do /*C*not*C*/ have an IR protection filter toward an image sensor /*C*or*C*/ were remodeled. This is important because unfiltered CCD /*C*and*C*/ CMOS sensors are extremely susceptible to UV /*C*and*C*/ IR rays just outside the visible spectrum that can have a very negative impact on image quality.

B. Main Uses /*C*and*C*/ Performance

• Suitable for color CMOS /*C*and*C*/ CCD cameras /*C*and*C*/ modified DSLRs.
• Use with monochrome CCD for astrophotography.

C. Spectral Curve Transmission Characteristics

• 95% transmission at visible spectral region 420-680nm highly passing the major nebula emission lines of H-Alpha 656nm, SII 672nm /*C*and*C*/ NII 654nm /*C*and*C*/ 658nm.
• Ultraviolet 300-400nm /*C*and*C*/ infrared wavelength 700-1100nm cut-off.
• 0.1% transmission of ff-band wavelengths.

D. Technical Specifications

• Both surfaces are fine optically polished, accurate to 1/4 wavelength /*C*or*C*/ better, /*C*and*C*/ parallel to within 30 seconds /*C*or*C*/ arc.
• 2mm thick Schott B270 optical glass substrate material.
• Very high surface quality of 60/40 /*C*or*C*/ better (US Military Spec MIL-O-13830).

E. Optical Coating Specifications

• Multi layer anti-reflection coated.
• Non-cementing optical substrate coating.
• Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability /*C*and*C*/ resistance to scratching, as well as stability on CWL (central wavelength) so that there is no deviation due to temperature changes during use.
• Precise /*C*and*C*/ homogeneous coatings ensure high values of desired passband /*C*and*C*/ blocking of unwanted offband.
• Every single filter is tested /*C*and*C*/ passed by Optolong before shipping to dealers.

F. Other

• 2' astronomy filter with standard M48x0.75 male filter thread (no female thread, so it cannot be stacked with other filters).
• Ultra-thin filter cell to minimize vignetting; clear optical aperture of 26mm.
• Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, /*C*and*C*/ laser engraving.
• High quality protective plastic storage case.