The invention features devices and methods for collecting and measuring light from external light sources. In general, the devices of the invention feature a light diffusing element, e.g., as a component of a light collector, connected by a light conducting conduit, e.g., a fiber optic cable, to a light measuring device, e.g., a spectrometer. This light diffusing element allows, e.g., for substantially uniform light diffusion across its surface and thus accurate measurements, while permitting the total footprint of the device to remain relatively small and portable. This light diffusing element also allows flexibility in scaling of the device to permit use in a wide range of applications.