Results 141 to 150 of about 1,126,700 (167)

Astronomy and the Extreme Ultraviolet Explorer Satellite

Science, 1994
The extreme ultraviolet wave band (100 to 912 angstroms) was thought until recently to be useless to astronomy, primarily because the opacity of the interstellar medium would prevent observations at these wavelengths. However, the interstellar medium has been found to be markedly inhomogeneous in both density and ionization state and the sun is ...
S Bowyer, Stuart Bowyer
exaly   +3 more sources

Aspheric Grating for Extreme Ultraviolet Astronomy

Applied Optics, 1978
A family of plane curves is developed which can diffract incident parallel rays to a point focus. These curves, termed diffractoidal curves, are rotated around an axis to produce surfaces of revolution correspondingly termed diffractoids, whose imaging properties for sources at infinity are studied by ray tracing in a few examples.
S O Kästner
exaly   +3 more sources

Selection of Materials for Soft x-Ray (SXR) and Extreme Ultraviolet (EUV) Filters for Space Astronomy and Other Applications

SPIE Proceedings, 1994
This paper briefly reviews the more traditional materials that have been used for Soft X-Ray (SXR) and Extreme Ultraviolet (EUV) filters and then discusses several applications where new multilayer combinations of materials are being employed. The new applications include projection lithography and the detection of Energetic Neutral Atom (ENA ...
Bill Sandel, Donald Mitchell, Forbes R Powell   +2 more
exaly   +2 more sources

The Design of an Echelle Spectrometer for Diffuse Extreme Ultraviolet/Far Ultraviolet Astronomy

Proceedings of SPIE, 1986
The novel, relatively high-resolution nebular spectrometer design presented incorporates a mechanical precollimator with an objective echelle grating that proceeds to a cross-dispensing Wadsworth configuration; the minimum feasible number of reflections is employed in order to maximize EUV sensitivity. The configuration, which is noted to be capable of
Christopher Martin
exaly   +2 more sources

Extreme-Ultraviolet Refractive Optics

Nature, 2018
Refraction is a well-known optical phenomenon that alters the direction of light waves propagating through matter. Microscopes, lenses and prisms based on refraction are indispensable tools for controlling the properties of light beams at visible ...
Bernd Schütte, Lorenz Drescher, Marc J J Vrakking   +2 more
exaly   +2 more sources

Extreme Ultraviolet Astronomy

1991
exaly   +2 more sources

Polarimetry of extreme ultraviolet lines in solar astronomy

Optical Engineering, 1991
Several mechanisms can induce a detectable amount of linear polarization (≥l%) in spectral lines emitted by the outer solar atmosphere at EUV/FUV wavelengths (i.e., 100 Å ≤ λ ≤ 1500 Å): (1) Polarization in FUV lines (up to 20%) can be originated by resonance scattering of radiation anisotropically illuminating the emitting atoms ...
Silvano Fineschi, Richard B. Hoover, Juan M. Fontenla, Arthur B. Walker   +3 more
openaire   +1 more source

Ultrasmooth beryllium substrates for solar astronomy in extreme ultraviolet wavelengths

Applied Optics, 2019
The paper describes a multistage method of forming ultrasmooth substrates based on bulk beryllium. Such substrates are suggested to be used for multilayer extreme ultraviolet mirrors of spacecraft missions on solar corona investigations in the spectral range 17.1-58.4 nm. The technique for chemical nickel plating of the sample surface is described. The
N. I. Chkhalo, M. S. Mikhailenko, A. E. Pestov, V. N. Polkovnikov, M. V. Zorina, S. Yu. Zuev, D. S. Kazakov, A. V. Milkov, I. L. Strulya, V. A. Filichkina, A. S. Kozlov   +10 more
openaire   +2 more sources

Advanced materials for multilayer mirrors for extreme ultraviolet solar astronomy

Applied Optics, 2016
We provide an analysis of contemporary multilayer optics for extreme ultraviolet (EUV) solar astronomy in the wavelength ranges: λ=12.9-13.3  nm, λ=17-21  nm, λ=28-33  nm, and λ=58.4  nm. We found new material pairs, which will make new spaceborne experiments possible due to the high reflection efficiencies, spectral resolution, and long-term ...
S A, Bogachev, N I, Chkhalo, S V, Kuzin, D E, Pariev, V N, Polkovnikov, N N, Salashchenko, S V, Shestov, S Y, Zuev   +7 more
openaire   +2 more sources

Extreme Ultraviolet Astronomy

Scientific American, 1994
▪ Abstract Astronomical studies in the extreme ultraviolet (EUV) band of the spectrum were dismissed during the early years of space astronomy as impossible, primarily because of the mistaken view that radiation in this band would be absorbed by the interstellar medium.
openaire   +1 more source