Fig. 1: IDL-map of current distribution
of Callisto instruments in May 2012.
The CALLISTO spectrometer is a programmable heterodyne receiver
build by ETH Zürich, Radio and Plasma Physics Group (PI Christian
Monstein). It operates between 45 and 870 MHz using a modern,
commercially available broadband cable-TV tuner CD1316 having a
frequency resolution of 62.5 KHz. The data obtained from CALLISTO are
FIT-files with up to 400 frequencies per sweep. The data are
transferred via a RS-232 cable to a computer and saved locally. Time
resolution is in the order of 0.25 sec, depending on the number of
channels. The integration time is 1 msec and the radiometric bandwidth
is about 300 KHz. The overall dynamic range is larger than 50 dB.
For convenient data handling several IDL routines were written.
Several
of the CALLISTO instruments have already been deployed,
including spectrometers in India (two in Ooty and one in Gauribidanur),
one in Badary near Irkutsk, Russian Federation, two in South Korea,
one in Australia (Perth and Melbourne), one in Hawaii, one in Mexico,
one in Costa Rica, two in
Brazil, three in Mauritius, three in Ireland, one in Czech Republic,
two in Mongolia, three in Germany, two in Alaska, one in Kazakhstan,
one in Cairo, one in
Nairobi, one in Pune, one in Sri Lanka one in Ahmedabad, one in Trieste
one in Slovakia and two in Belgium.
Through the IHY/UNBSSI
instrument deployment program, CALLISTO is able to continuously observe
the solar radio spectrum for 24h per day through all the year. All
Callisto spectrometers together form the e-Callisto network.Callisto in
addition
is dedicated to do radio-monitoring within its frequency range with
13'200 channels per spectrum. The frequency range can be expanded to
any range by switching-in a heterodyne up- or a down-converter.
