The STS-VIS-RAD spectrometer delivers the performance you need, whether you are in the lab or in the field doing your upwelling/downwelling measurements. The STS-VIS-RAD provides powerful spectral performance in a small footprint.This compact instrument comprises a radiometrically calibrated STS-VIS spectrometer with direct-attach cosine corrector, and is ideal for irradiance applications including LED characterization. Its rugged design and great unit-to-unit reproducibility make STS-VIS-RAD attractive for integration into high-volume applications such as LED sorting on a production line.When you specify an STS-VIS-RAD for your application, you will benefit from our experience in radiometrically calibrating spectral systems and be ready to take measurements right out of the box. An absolute irradiance measurement yields a spectrum that is accurate in shape and magnitude. Typically, the y-axis is expressed in power or flux units, from which other measurements can be derived. We calibrate the system with the cosine corrector attached; removing the cosine corrector will invalidate the calibration.