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EUV Full-Sun Imaging and Pointing Calibration of the SOHO Coronal Diagnostic Spectrometer
Thompson, William; Carter, Martin
Although the field of view of the Normal Incidence Spectrometer (NIS) of the Coronal Diagnostic Spectrometer (CDS) is 4×4 arc min, it is possible to observe the full solar disk by forming a mosaic of images taken in succession. This paper describes just such a study which has been used to collect images of the Sun simultaneously in six wavelengths…
Ultraviolet Observations of a Dynamic Event in the Solar Corona
Dwivedi, B. N.; Wilhelm, K.; Curdt, W. +1 more
The Solar Ultraviolet Measurements of Emitted Radiation instrument (SUMER) observations show high Doppler shifts and temporal variations in profiles of ultraviolet lines from low temperature gas in the corona above the active region NOAA 7974. The profiles indicate ≈ 100 km s-1 flows coming from an almost stationary source that appears …
Visualization of three-dimensional datasets
Walsh, Robert W.; Ireland, Jack; Galsgaard, Klaus
The effective visualization of three-dimensional (3d) datasets, both observationally and computationally derived, is an increasing problem in solar physics. We present here plots of computational data derived from the 3d reconstruction of the magnetic field of a loop system, rendered as anaglyphs. By combining images of the same 3d object from two…
First Results from the SOHO Ultraviolet Coronagraph Spectrometer
Romoli, M.; Raymond, J. C.; Naletto, G. +23 more
The SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) is being used to observe the extended solar corona from 1.25 to 10 R⊙ from Sun center. Initial observations of polar coronal holes and equatorial streamers are described. The observations include measurements of spectral line profiles for HI Lα and Lβ, Ovi 1032 Å and 1037 Å, Mgx 625 Å, Fexi…
EIT Observations of the Extreme Ultraviolet Sun
Michels, D. J.; Gurman, J. B.; Berghmans, D. +32 more
The Extreme Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft has been operational since 2 January 1996. EIT observes the Sun over a 45 x 45 arc min field of view in four emission line groups: Feix, x, Fexii, Fexv, and Heii. A post-launch determination of the instrument flatfield, the instrument scattering function, and the instrume…
First Results of the SUMER Telescope and Spectrometer on SOHO - I. Spectra and Spectroradiometry
Vial, J. -C.; Grewing, M.; Wilhelm, K. +16 more
SUMER - the Solar Ultraviolet Measurements of the Emitted Radiation instrument on the Solar and Heliospheric Observatory (SOHO) - observed its first light on January 24, 1996, and subsequently obtained a detailed spectrum with detector B in the wavelength range from 660 to 1490 Å (in first order) inside and above the limb in the north polar corona…
Composition of Coronal Streamers from the SOHO Ultraviolet Coronagraph Spectrometer
Romoli, M.; Raymond, J. C.; Naletto, G. +24 more
The Ultraviolet Coronagraph Spectrometer on the SOHO satellite covers the 940-1350 Å range as well as the 470-630 Å range in second order. It has detected coronal emission lines of H, N, O, Mg, Al, Si, S, Ar, Ca, Fe, and Ni, particularly in coronal streamers. Resonance scattering of emission lines from the solar disk dominates the intensities of a…
Structure and Rotation of the Solar Interior: Initial Results from the MDI Medium-L Program
Kosovichev, A. G.; Hoeksema, J. T.; Scherrer, P. H. +31 more
The medium-l program of the Michelson Doppler Imager instrument on board SOHO provides continuous observations of oscillation modes of angular degree, l, from 0 to ∽ 300. The data for the program are partly processed on board because only about 3% of MDI observations can be transmitted continuously to the ground. The on-board data processing, the …
First Results from VIRGO, the Experiment for Helioseismology and Solar Irradiance Monitoring on SOHO
Gough, Douglas; Domingo, Vicente; Appourchaux, Thierry +19 more
First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observations started mid-January 1996 for the radiometers and sunphotometers and near the end of March for the luminosity oscillation imager. The performance of all t…
First Results of the SUMER Telescope and Spectrometer on SOHO - II. Imagery and Data Management
Grewing, M.; Wilhelm, K.; Marsch, E. +13 more
SUMER - Solar Ultraviolet Measurements of Emitted Radiation - is not only an extreme ultraviolet (EUV) spectrometer capable of obtaining detailed spectra in the range from 500 to 1610 Å, but, using the telescope mechanisms, it also provides monochromatic images over the full solar disk and beyond, into the corona, with high spatial resolution. We …