EIT - Extreme Ultraviolet Imaging Telescope

- Joe Gurman

The SOHO EIT is able to image the solar transition region and inner corona in four, selected bandpasses in the extreme ultraviolet (EUV):

     Fe IX/X, 171 Å
     Fe XII, 195 Å
     Fe XV, 284 Å
     He II, 304 Å
Using either full-disk or subfield images, the EIT can image active regions, filaments and prominences, coronal holes, coronal "bright points," polar plumes, and a variety of other solar features. The instrument was designed to be used in conjunction with other SOHO instruments, particularly the LASCO visible-light coronagraphs and the SUMER and CDS imaging spectrographs, as well as with ground-based instruments.

This first image is of 1-million degree Celsius gas in the Sun's thin, outer atmosphere (corona) was taken by the Extreme Ultraviolet Imaging Telescope (EIT) in the Fe IX/X emission lines at 171 Å. It is followed by a 1.5-million degree 195 Å image (green) and a 2-million degree 284 Å image (yellow). The 304 Å bandpass allows EIT to image cooler plasma in the upper chromosphere.

The synoptic observing plan has consisted of full-field full-resolution images in all four wavelengths, once per day, along with three half-resolution images in each wavelength. These are supplemented by 195 Å half-res images every 2 hours. A new synoptic program will be initiated in January 1997, consisting of four full-field full-resolution images in each wavelength daily.

EIT full sun images in Fe XII 195 A (left), Fe IX/X 171 A (middle), and the ratio of these two images (right). The latter one gives an indication of the temperature distribution in the Sun's corona with dark areas being cooler regions and bright areas being hotter. These images were recorded on 12 May 1996.

Dr. Gurman completed the talk with a videotape of EIT events. The EIT homepage contains a variety of .gif movies of EIT observations.

Return to ISTP SOHO Workshop Page


EVENT LISTS - Possible Targets for Correlative Study

POINTS OF CONTACT - Participants in coordinated investigations

DATA LINKS - Data sites and starting points for various instruments and data facilities


This page was created 6 January 1997.
This page was revised on 12 January 1997.
Barbara J. Thompson