Nancay Radio Observatory, France
The Nancay Radio Observatory is a scientific department of the Paris Observatory and consists of four different instrumentations:
- Radioheliograph
Radio observations of the Sun at these wavelengths (between 0.6 and 2 meter) essentially mean a study of the extremely hot gas surrounding the visible solar disk, the corona. In visible light, the corona can only clearly be seen from Earth during a total solar eclipse; optical solar telescopes with a disk eclipsing the Sun (so-called coronagraphs) can provide us only with a look at the brightest part of the inner corona, close to the visible surface. At Nancay the outer corona can be observed at radio wavelengths, from about 0.1 to 0.5 times the radius of the visible solar disk above the visible limb of the Sun.
- Decameter array
The Decametric Array of Nançay (RDN) is dedicated to the study of the magnetic and ionized environment of planets (mainly Jupiter), the Sun and stars. In these plasmas not only the low-frequency emission (decametric radio waves) detected with the Decametric Array are produced, but also very low frequency emission (at kilometric wavelengths) and ultraviolet radiation (planetary aurorae).
The radio observations show a variety of phenomena (down to time scales of less then a second: the so-called millisecond bursts of Jupiter, and solar and stellar eruptions) which allow the study of the dynamics of these ionized plasma environments.
- Radiotelescope
The Decimetric Radio Telescope consists of a flat mirror which reflects radio waves towards, a spherical mirror which send them on to and a focal carriage where they are being collected for analysis. It's capable of observing objects with a declination greater that −39°. Objects near the equator can only be tracked for about an hour, but objects nearer the zenith can be tracked for longer. Observations are typically undertaken at frequencies of 1,400 MHz (equivalent to a wavelength of 21 cm), 1,660 MHz (18 cm) and 3,330 MHz (9 cm).
- VLF antenna
The VLF and ELF radio receivers can be used extensively for remote sensing of the ionosphere and the magnetosphere. Among the phenomena that can be uniquely measured are radio atmospherics, whistlers, electron precipitation, solar flares, sudden ionospheric disturbances, gravity waves, sprites, and cosmic gamma-ray flares. They use a simple square air-core magnetic loop antennas of a couple of meters in size, the sensitivity allows the measurement of magnetic fields as low as several tens of femtoTesla per root-Hz, in the frequency range of ~30 Hz to 50 kHz.
Resources:
- Nancay Radio Observatory, department of Paris Observatory:
- BASS2000 Database (includes data from Nancay Radioheliograph and Decametric Array):
