Affiliations: Laboratory for Spectroscopy, P. N. Lebedev Physical
Institute of Russian Academy of Science, Leninsky pr. 53, Moscow, 117924,
Russia. Tel.: +7 95 135 8081; Fax: +7 95 938 2251, +7 95 135 2408; E-mail:
[email protected]. | Laboratory for Astronomy and Solar Physics,
NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA.
Abstract: The RES-C grazing incidence XUV spectroheliograph has been developed
in the P. N. Lebedev Physical Institute (FIAN) as a part of the CORONAS-I
project. Its objective is to obtain images of the full Sun in monochromatic
lines over the spectral range of 180210Å, which includes prominent
emission from ions of Fe VIIIFe~XIII, O VI, and Fe XXIV. Here, we describe
the optical scheme of the spectroheliograph, and show results of XUV testing of
its individual component elements as well as of the complete assembled
instrument. XUV measurements were made of the absolute diffraction efficiency
and stray-light level for both holographic and mechanically ruled gratings, the
spectral reflectivity of the multilayer-coated mirrors, the transmittance of
the thin aluminum blocking filters, and the combined spectral efficiency of the
whole instrument. The spectral and spatial resolutions of the spectroheliograph
were measured by recording spectrally dispersed images of a laser plasma source
in monochromatic lines of fluorine ions between 185200Å. For comparison,
we also present spectral images of the Sun obtained with the spectroheliograph
as flown on the CORONAS-I satellite mission.
