EIT: The extreme ultraviolet imaging telescope

Abstract

The EIT will provide wide-field images of the corona and transition region, on the solar disc and up to 1 Rθ above the limb. Its normal incidence multilayer-coated optics will select the spectral emission lines of four ions (FeIX, 171 Å; FeXII, 195 Å; FeXV, 284 Å; HeII, 304 Å), providing a sensitive temperature diagnostic in the range 6.10 4 to 3.106 K. This SOHO instrument will thus probe the coronal plasma on a global scale, as well as the underlying cooler and turbulent atmosphere. The EIT's characteristics and performances are presented, and prospects for coordinated observations with ground-based radio observatories are outlined.