Location: Observatorio del Teide, Spain
Owner: Centre National de la Recherche Scientifique (CNRS, France) and Consiglio Nazionale delle Ricerche (CNR, Italy)
The Télescope Héliographique pour l'Etude du Magnétisme et des Instabilités Solaires (THEMIS) is a joint venture of CNRS/INSU (France) and INAF (Italy). It is located at Observatorio del Teide in Tenerife, 2400 m above the sea level. It is a 90 cm aperture solar telescope and currently the third largest in the world. Its design allows for high-accuracy spectropolarimetry of the solar surface together with monochromatic high-resolution imaging. The telescope is filled with helium to improve image quality.