Research Instruments

Members of the U of M Solar Physics Group use data collected from the following instruments in their research.

SERTS

The Solar EUV Research Telescope and Spectrograph (SERTS) instrument obtains spatially resolved spectra and spectroheliograms over a wide range of extreme ultraviolet (EUV) wavelengths, characteristic of temperatures between 5 x 104-3 x 107 K . SERTS has been flown successfully a number of times, providing exquisite and unique scientific data. The spectra obtained are the highest quality, highest resolution ever obtained in the 170-450 Å wavelength range.

A strength of the SERTS data stems from the fact that this spectral range is rich with emission lines. Over 240 lines from 57 different ions are seen in the SERTS active Sun spectrum. For example, multiple lines are observed for all ionization states of iron from Fe IX to Fe XVII. These allow accurate calibration with a large number of lines covering the instrument's entire wavelength range.

The SERTS instrument was conceived in the late 1970's as a follow-on to the Skylab SO-82A spectroheliograph. The first fully successful flight of SERTS was in May of 1989. Since that time there have been ten flights with improved instrumentation resulting in better spatial and spectral resolution. Most notable have been the incorporation of multilayer optics, and an intensified CCD detector.

DATA

SERTS pointing position showing lobe alignment over active region. Small green box is CDS coverage of same active region.

SOHO

SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by Matra, and instruments were provided by European and American scientists. There are nine European Principal Investigators (PI's) and three American ones. Large engineering teams and more than 200 co-investigators from many institutions supported the PI's in the development of the instruments and in the preparation of their operations and data analysis. NASA was responsible for the launch and is now responsible for mission operations. Large radio dishes around the world which form NASA's Deep Space Network are used to track the spacecraft beyond the Earth's orbit. Mission control is based at Goddard Space Flight Center in Maryland.

CDS

The Coronal Diagnostic Spectrometer (CDS) is designed to obtain spectra-spectroheliograms in a number of lines simultaneously in the extreme ultraviolet (EUV) region of the electromagnetic spectrum. CDS addresses two of the three main goals of SOHO, namely, (i) Why does the corona exist, how is it heated, and (ii) How are the solar wind-streams accelerated? Critical to the pursuit of these goals is the determination of plasma characteristics (densities, temperatures, velocities, abundances etc...) on spatial, temporal and spectral scales and ranges appropriate to those of the solar atmosphere. The CDS experiment is designed to determine such information through the study of emission line characteristics in the extreme ultraviolet (EUV) - particularly essential for the detection of emission from the hottest plasmas in the (non-flare) solar atmosphere. This is complementary to the remaining coronal instrument package on SOHO which includes a longer-wavelength UV spectrometer, an EUV imager and two coronagraphs (UV and white light).

DATA

EIT

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.

DATA

TRACE

TRACE enables solar physicists to study the connections between fine-scale magnetic fields and the associated plasma structures on the Sun in a quantitative way by observing the photosphere, the transition region, and the corona. With TRACE, these temperature domains are observed nearly simultaneously (with as little delay as only a second between different wavelengths), with a spatial resolution of one second of arc.

This is accomplished by obtaining precisely coaligned image sequences of photosphere, transition region, and corona, with high spatial resolution and uninterrupted viewing of the Sun for up to eight months.

DATA

This image of coronal loops over the eastern limb of the Sun was taken in the TRACE 171Å pass band, characteristic of plasma at 1 MK, on November 6, 1999, at 02:30 UT. The image was rotated over +90 degrees.

Yohkoh

On August 30, 1991 a satellite was launched into space from the Kagoshima Space Center (KSC) in Southern Japan. This satellite, known as Yohkoh ("Sunbeam"), is a project of the Japanese Institute of Space and Astronautical Science (ISAS). The scientific objective has been to observe the energetic phenomena taking place on the Sun, specifically solar flares in x-ray and gamma-ray emissions. Yohkoh stopped taking data on December 14, 2001 due to a lunar eclipse. The spacecraft experienced attitude control problems when the moon moved in the spacecraft's field of view; more about the accident can be found here.

There were four instruments on Yohkoh that detect energetic emissions from the Sun:

• the Bragg Crystal Spectrometer (BCS)
• the Wide Band Spectrometer (WBS)
• the Soft X-Ray Telescope (SXT)
• the Hard X-Ray Telescope (HXT).

SXT

DATA

This is an SXT image of the sun taken at 07:33 UT on 12 November 1991. Three separate exposures of 9.5, 78, and 2668 milliseconds were combined in this image. Picture brightness scales as the logarithm of intensity. A thin aluminum filter restricted the instrument bandpass to the 3 to 40 Angstrom wavelength interval. The hot ionized gases in the solar atmosphere which emit in this interval trace the solar magnetic fields extending up into the corona. Variation in brightness reflect variations in plasma temperature and density.

All information for this page was taken directly from the official sites of the instruments listed above.