High Quality Content by WIKIPEDIA articles! The "Sun Watcher using Active Pixel System Detector and Image Processing" (SWAP) telescope is a compact EUV imager on board the PROBA2 mission that will observe the Sun in extreme ultraviolet (EUV). SWAP will provide images of the solar corona at a temperature of roughly 1 million degrees. This instrument was built upon the heritage of the Extreme ultraviolet Imaging Telescope (EIT) which monitors the solar corona since 1996.