Observations of the solar atmosphere from the Solar and Heliospheric Observatory (SOHO).

Abstract

The Solar and Heliospheric Observatory (SOHO) spacecraft was launched on December 2, 1995, into a halo orbit around the first Lagrangian Point L1 between Sun and Earth, carrying into space a payload of twelve Sun observing instruments. Among them is a set of four complementary telescope/spectrometers to study phenomena and dynamics of the Sun's atmosphere in the far or extreme ultraviolet: The Extreme-Ultraviolet Imaging Telescope (EIT), the Coronal Diagnostic Spectrometer (CDS), the Solar Ultraviolet Measurements of Emitted Radiation (SUMER), and the Ultraviolet Coronagraph Spectrometer (UVCS). The spectral coverage of these instruments, which extents from 151 to 1610 Å, allows remote sensing investigations of the solar atmosphere by means of spectroscopic and imaging techniques with a spatial resolution down to 1 arcsec. Each one of these instruments by itself is a technological achievement making use of normal incidence, grazing incidence, or multilayer optical techniques to cover the appropriate spectral ranges for each scientific objective. Many of the plasma diagnostic studies have been carried out during the first months of the mission, and this contribution will give an overview of the capabilities of each instrument and the types of observations being made by individual and joint operations.