The Extreme Ultraviolet Imager (EUVI) is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU.

EUVI measured emission lines at 30.4 nm (He II), 17.1 nm (Fe IX), 19.5 nm (Fe XII), and 21.1 nm (Fe XIV). The EUVI's 2048 x 2048 pixel detectors have a field of view out to 1.7 solar radii, and observe in four spectral channels that span the 0.1 to 20 MK temperature range. In addition to its view from two vantage points, the EUVI will provide a substantial improvement in image resolution and image cadence over its predecessor SOHO-EIT, while complying with the more restricted mass, power, and volume allocations on the STEREO mission.