The paper describes instruments for solar imaging XUV spectroscopy -- the TEREK-C telescope array and the RES-C spectroheliograph mounted on board the Russian-Ukrainian CORONAS-I satellite (launched on March 2, 1994). The CORONAS project is carried out under scientific guidance of Prof. V.N. Oraevsky, director of the IZMIRAN (Troitsk, Moscow region, Russia) -- leading institute of this project. The instruments were intended to obtain high resolution solar images and spectra from the transition region and the corona of the Sun within the temperature range of 10⁵ - 10⁷ K. The optical design of the TEREK telescope array includes two Herschelian XUV-telescopes with Mo-Si multilayer mirrors: the first one with 3 whole-Sun spectral channels (reflection peaks at (lambda) equals 13.2, 17.5 and 30.4 nm, angular scale 4.7'), the second channel -- with 4 mirrors, each covering 1/4 of the Sun ((lambda) equals 17.5 nm, angular scale 1'). The RES-C spectroheliograph has five measuring channels with a whole-Sun field of view: two XUV channels with orthogonal dispersion planes, equipped with grazing incidence gratings and multilayer mirrors to obtain high resolution spectral images in the 19.2 - 20.1 nm band (spectral resolution 2 (DOT) 10^-4 nm/pix, angular scale 4.5'), two MgXII channels having narrow-band imaging systems with orthogonal dispersion planes for the 0.841 - 0.843 nm spectral band, equipped with Bragg crystal spherical mirrors, and one FeXXV imaging system with a ring Bragg crystal mirror for the 0.184 - 0.188 nm spectral band. Two types of image detectors were designed with the use of CCD-matrices (1024 X 1152 elements) and image intensifiers (with an open microchannel plate and a luminescent converter). The paper presents a detailed description of the overall structure, electronic design and the main characteristics of the instruments, preliminary results of flight functioning of the TEREK-C and RES-C instruments and examples of the images and spectra of the Sun obtained in the experiment.

The paper describes the main characteristics of the X-ray optical elements (multilayer spherical and aspherical mirrors and diffraction gratings for the 13-30 nm XUV spectral region, Bragg crystal spherical mirrors for the 0.18 and 0.84 m soft X-ray spectral regions) manufactured for the TEREK-C solar XUV telescope array and the RES-C solar spectroheliograph. The TEREK-C and RES-C instruments were placed aboard the CORONAS-I satellite which was launched on March 2, 1994. The testing procedures and results of laboratory tests in X-ray spectral range are also presented.

The characteristics of different types of thin film XUV filters for the TEREK-C solar telescope and the REC-C spectroheliograph developed in the framework of the CORONAS-I program are presented. We describe the design and properties of Al-Formvar composite filters on rigid mesh supports with a spacing of 0.7 mm and 2 mm, which have been mounted in front of the XUV spectral channels of both instruments. It was proposed to use thin films of SiC as bandpass filters with high transparency in the 13 - 30 nm spectral region and effective cutoff blocking of strong solar L_α (121.7 nm) line radiation. The Al and SiC thin films on fine porous polymer membranes with through pores were placed in close proximity of the entrance plane of the image detectors, designed as a combination of open type microchannel plate and CCD-matrix. The problem of elimination of the influence of diffraction effects on X-ray images in the telescope focal plane is considered. All filters have sustained without damage the launching overloads (the launch took place on March 12, 1994) and successfully worked in the TEREK-C and the RES-C instruments.

We report the experimental results on production of multilayer soft x-ray and EUV mirrors and their application in x-ray spectroscopy and fluorescence analysis, as well as for development of EUV lithographic and x-ray microscopic devices and soft x-ray point sources. The problem of the production and the investigation of short-period x-ray multilayers and multilayer (gamma) -filters is discussed.

Ultrathin Cr/Sc-multilayers were systematically investigated using tuneable soft x-ray synchrotron and x-ray tube radiation. The multilayers were optimized either for use in normal incidence or at 45 degrees at photon energies around the L-absorption edges of Sc (399 eV) and Cr (574 eV), respectively, and K-absorption edge of C (283 eV). The high reflectivity of the multilayer mirrors allows to use them for the creation of multi-mirror systems for x-ray astronomy and microscopy and x-ray diagnostics of high-temperature plasma.

Spectral characteristics of plane multilayer amplitude molybdenum-silicon diffraction gratings (1000 and 2000 lines/mm, d-spacing of 115 angstrom), fabricated by electron- beam lithography, were determined using a laser-produced plasma XUV radiation source. The gratings were studied at near-normal incidence and at an angle of incidence of 36 degrees in stigmatic and quasi-stigmatic spectrograph systems with moderate dispersion. The task of focusing radiation was imposed on either a grazing-incidence toroidal mirror or a normal-incidence Mo-Si multilayer mirror with a d-spacing of 115 angstrom. The spectral profile of resonance reflection by the gratings was determined in the first and second Bragg orders of the multilayer structure for different angles of incidence. Line spectra of multiply charged F, Na, Mg, and Cl ions were recorded in the 160 - 230 angstrom range by means of these multilayer gratings, and the resolving power of the gratings was determined.

The design and characteristics of a von Hamos spectrograph are considered. Efficiency of the von Hamos mica crystal spectrograph is absolutely calibrated using laser-produced plasmas as an x-ray source and a p-i-n diode as a detector. The value of integrated reflectivity of the mica crystal is also determined in the same spectral bands and diffraction orders: 5.5 - 11 angstrom (first order), 2.6 - 5.0 angstrom (second order), 1.84 - 3.22 angstrom (third order), 1.84 - 2.65 angstrom (fourth order), 1.84 - 1.92 angstrom (fifth order). The von Hamos spectrograph is used for x-ray spectroscopy and radiometry of laser-produced plasmas. The spectrograph possesses several advantages of interest: high spectral resolution ((lambda) /(delta) (lambda) up to 3000), a direct registration of one or two dimensional source images (spatial resolution up to 10 micrometers) and a high detecting efficiency over a wide spectral range. Focused intensities could be 10² - 10³ times higher than those of flat crystal spectrographs. This type of spectrograph is ideal for the recording of the wide-range x-ray spectra of low intensity sources such as the femtosecond laser-produced plasma, micropinch, electron beam ion trap (EBIT), and others.

Absorption of solar UV-radiation in the 250 - 280 nm band by ozone layer leads to very low background of radiation scattered by the Earth at altitudes above 80 km. It makes possible to observe from near-Earth orbit with high sensitivity processes in upper atmosphere caused by engines of rockets and spacecrafts during their maneuvering or entering into dense layers of atmosphere. The main characteristics and application of the high sensitive imaging UV-camera specially designed for observations on-board the <<Mir>> manned orbital station (OS) are described. The camera works in the 200 - 350 nm spectral region and includes catadioptric objective, narrow band filters, special UV-sensitive image intensifier, photographic camera or TV-camera. Images are registered with sensitivity of 4 (DOT) 10¹⁶ w/cm² in FOV of 12 degrees with angular resolution of 1,5'. The camera was delivered on-board the <<Mir>> OS in July 1992 and successfully worked during 5 years. Examples of observations of different space objects are given.

This paper presents a first-order performance analysis of the Multichannel Infrared Spectroradiometer (MIRS) and the Visible-Infrared TV-monitor and Atmospheric Refractometer (VISIR) as the integral parts of the ISTOK-1 set of instruments that are working on the scientific module 'Priroda' of the 'Mir' orbital station. The diffraction polychromator MIRS measures thermal emission and absorption spectra of the atmosphere in the wavelengths region 4 - 16 micrometer with the spectral resolution of 0.15 - 0.3 micrometer. The CID TV-camera VISIR measures the atmospheric refraction angles by observation of the Sun rises and sets at wavelengths 1004 - 1024 nm with the accuracy of 20 arc. sec. The optical instruments are mounted upon a two-axle rotary platform which can be controlled directly by the navigation system of the station. The objectives of the ISTOK-1 experiments are the development of the methods of ecological monitoring and meteorological sounding of the Earth: tests of the new types of satellite-borned monitors, measurement geometry, simultaneous using of spectrometry and refractometry of the atmosphere. The ISTOK-1 system on the whole, its optical instruments and their pre-flight tests are discussed.

MM-wave heterodyne spectroscopy is successfully used for measuring of the atmospheric ozone at altitudes from about 15 to 80 km. Remote sensing of trace gases, including ozone at MM waves has a number of obvious advantages. The required performance of a ground-based instrument for ozone observations at wavelength of 2 mm has bene determined using results of computer simulations. Main features of the Lebedev Physics Institute heterodyne radio spectrometer for 142.2 GHz ozone spectral line measurements are described, and key parts of the spectrometer receiver, such as input optics and low- noise Schottky diode mixer, are considered in greater detail. The receiver and the mixer have been tested throughout the 22- mm band at both room and liquid nitrogen temperatures and main results of the tests are presented. Blackbody cold loads have been used in the calibration/observation procedure, with special attention paid to accurately measuring their brightness temperatures. Some results of ozone observations for various atmosphere states are presented to demonstrate possibilities of ground-based MM-wave heterodyne spectroscopy.