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 several 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. Click here for a table which summarizes the SERTS flight configurations.
Instrument
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, providing information about the Sun's corona and upper transition region. Wavelength coverage is 170-450 Å with spectral resolution near 10000, spatial resolution as good as 5arcsec, and relative photometric accuracy within +/- 20% over most of its range. Recent flights featured an improved Ritchey-Chetien telescope and a multilayer-coated grating that significantly increased the instrument's sensitivity with no loss in spectral resolution. SERTS was developed by the Solar Physics Branch of NASA's Goddard Space Flight Center, under the original leadership of Dr. Werner M. Neupert. The Principal Investigator since 1990 has been Dr. Joseph M. Davila.
Observations
SERTS has now flown a total of ten times, providing exquisite and unique scientific data. Observations included active region loops, quiet Sun areas, coronal holes, Sunspots, filament channels, extended coronal emission above the limb, the beginning phase of a subflare, and possible counterparts to X-ray bright points. The resulting SERTS data represent the best quality, highest resolution spectral measurments ever obtained in the 170-450 Å wavelength range. A total of more than 270 emission lines from 60 different ions have been measured in the available SERTS spectra.
Science
These data have been used to examine a wide variety of scientific topics, including flows in the active and quiet Sun, determination of the coronal magnetic field, coronal abundance anomalies, density, temperature and filling factors for various solar features, the formation and excitation of He II 304, and verification of selected atomic theory calculations.
For those who would like more information, also available are:
Technology Development in the SERTS Rocket Program
Sounding rocket programs provide a relatively inexpensive way to develop new instrument technology and demonstrate it in space. SERTS has made significant contributions to developing spectroscopic instrumentation in the EUV. Here we provide information on some of the most significant developments.
Intensified CCD Detector Development -- Continued improvement in intensified CCD detectors has allowed SERTS to switch from film to an electronic detector without loss of resolution.
Telescope Development -- A high resolution grazing incidence telescope was developed and fabricated, and an even higher resolution normal incidence, multilayer-coated telescope has also been fabricated.
Diffraction Grating Performance Improvement Program -- SERTS flew the first multilayer-coated diffraction grating in space in 1991, demonstrating a factor of 6 improvement in efficiency over gold coatings.
Improved Entrance Slit -- Semiconductor fabrication techniques were adapted to fabricate a near perfect slit in a thin silicon wafer.
Last Revised: Wednesday, 29-Nov-2006 07:34:22 EST
Responsible NASA Official: joseph.davila@gsfc.nasa.gov
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