Rayls

Rayls are a unit of spectral irradiance. Spectral irradiance quantifies the power received per unit area per unit wavelength. Specifically, a rayl is defined as one watt per square meter per nanometer. This unit is commonly used in fields such as astronomy, optics, and atmospheric science, where the intensity of radiation across a spectrum of wavelengths is of interest. For instance, in astronomy, rayls can be used to describe the brightness of celestial objects at different wavelengths of light. In optics, they might be used to characterize the output of light sources. The rayl is a practical unit because it directly relates measured power to the area over which it is spread and the narrow band of wavelengths being considered. It is a component of the International System of Units (SI) but is often used in conjunction with SI base units.