The EKO Instruments RSR-01 shadow ring is an common economic solution to measure diffuse irradiation at any location on earth. The static Radiometer Shadow Ring RSR-01 can be used with all EKO Pyranometers (MS-802/402/410/602). Dedicated mounting adapters are available for other types of solar sensors (Spectroradiometers, MS-212, other brands).
The shadow ring in combination with one of those pyranometers provides high quality diffuse solar radiation measurements on site. The shadow ring ensures that the radiation sensor always remains in shade for several days before it requires re-adjustment.
For automatic diffuse solar radiation measurement the STR Sun Trackers series can be applied.