Solar physics assessment of future high-resolution observations in the Grazing-Incidence domain

The project for a Grazing Incidence Solar Telescope (GRIST) offers, for the first time, the combinations of high spatial (1) and spectral resolution in the extreme-ultraviolet wavelength range. The 3-dimensional electron density and temperature structure of the transition region and corona will be determined. The dynamics of the structures which make up the corona will be studied. GRIST can be expected to provide definitive improvement in the understanding of the coronal heating problem.Proceedings of the Conference Solar Physics from Space, held at the Swiss Federal Institute of Technology Zurich (ETHZ), 11–14 November 1980.     

The SOHO concept and its realisation

The Solar and Heliospheric Observatory (SOHO) — a space observatory to be placed, in 1995, 1.5 Gm sunward from the Earth in a halo orbit around the L1 Lagrange point — will investigate:

the solar corona, its heating and expansion into the solar wind, by both studying the radiation emerging from the outer solar atmosphere and in-situ solar wind measurements near 1 AU, and

the structure and dynamics of the solar interior by the method of helioseismology.

The science policy evolution leading to this comprehensive observatory concept is described. SOHO's link to the space-plasma-physics mission CLUSTER — devoted to the three-dimensional study of small structures in the magnetosphere — within the Solar Terrestrial Science Programme (STSP) and the embedding of STSP in the much larger International Solar Terrestrial Physics (ISTP) Programme are cited as well. The scientific subjects to be addressed by SOHO are introduced, and their current status assessed. Subsequently, the measurements required to advance these subjects are stated quantitatively and the payload, which will actually perform these measurements, is presented. The mission design, comprising spacecraft, orbit, operations and the data and ground systems are described. The special efforts made to obtain a reliable radiometric calibration of the instruments observing the Sun in the extreme-ultraviolet and to achieve a stable sensitivity through extreme cleanliness of spacecraft and instruments are emphasized and substantiated.     

The solar and heliospheric observatory,SOHO — A phase-A project of the European space agency

The Solar and Heliospheric Observatory is designed to address basic questions concerning the Sun and Heliosphere. In this paper our present understanding of coronal heating, solar wind generation and solar oscillations is described. The proposed model SOHO instrument payload is outlined and it is shown how it would contribute to our understanding in the above three fields.     

GRIST observations of non-solar objects: Observational constraints

The use of the Grazing Incidence Solar Telescope (GRIST) for the observation of celestial sources other than the Sun in the Extreme Ultraviolet (EUV) is discussed. By use of galactic point sources as sample objects, the capabilities offered by the presently proposed telescope and its focal plane instruments set are shown to be substantial, in spite of the short duration of a single Shuttle mission. This seems to legitimate complementary technical studies needed to demonstrate the feasibility of stellar pointing.Proceedings of the Conference Solar Physics from Space, held at the Swiss Federal Institute of Technology Zurich (ETHZ), 11–14 November 1980.