The interface region imaging spectrograph for the IRIS Small Explorer mission

Abstract

The Interface Region Imaging Spectrograph (IRIS) is a NASA SMall EXplorer mission scheduled for launch in January 2013. The primary goal of IRIS is to understand how the solar atmosphere is energized. The IRIS investigation combines advanced numerical modeling with a high resolution UV imaging spectrograph. IRIS will obtain UV spectra and images with high resolution in space (0.4 arcsec) and time (1s) focused on the chromosphere and transition region of the Sun, a complex interface region between the photosphere and corona. The IRIS instrument uses a Cassegrain telescope to feed a dual spectrograph and slit­jaw imager that operate in the 133­141 nm and 278­283 nm ranges. This paper describes the instrument with emphasis on the imaging spectrograph, and presents an initial performance assessment from ground test results.