International Network of Solar Radio Spectrometers, a Space Weather Instrument Array

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Map of current distribution of Callisto instruments in May 2019. Update rate ~15 minutes, press reload to see latest status. One dot can represent up to 5 instruments.

Statistics: more than 159 instruments at more than 98 locations worldwide.

Callisto stands for: Compound Astronomical Low cost Low frequency Instrument for Spectroscopy and Transportable Observatory

type II
Type II burst (Ooty)

The CALLISTO spectrometer is a programmable heterodyne receiver designed 2006 in the framework of IHY2007 and ISWI by Christian Monstein (PI) as member of the former Radio Astronomy Group (RAG) at ETH Zurich, Switzerland. The main applications are observation of solar radio bursts and rfi-monitoring for astronomical science, education and outreach. The instrument natively 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 0.25 sec at 200 channels per spectrum (800 pixels per second). 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-, PERL- and Python-routines were written.
Many CALLISTO instruments have already been deployed, including: 10 spectrometers in India (2 in Ooty, 1 in Gauribidanur, 1 in Pune, 1 in Ahmedabad, 1 in Sangli, 2 in Bagalore, 1 in Nashik and 1 in Udaipur), one in Badary near Irkutsk, Russian Federation, two in Daejeon/South Korea, three in Australia (Adelaide, Melbourne and Heathcote), two in Hawaii, two in Mexico, one in Costa Rica, two in San Jose dos Campos/Brazil, three in Mauritius, 5 in Birr/Ireland, one in Ondrejov/Czech Republic, two in Ulaan Baatar/Mongolia, one in Germany (Essen), three in Cohoe and Anchorage/Alaska, two in Almaty/Kazakhstan, one in Cairo/Egypt, one in Nairobi/Kenya, 3 in Sri Lanka, four in Italy (3 in Trieste and 1 in Turin), two in Slovakia (Hurbanovo and Rotztoky), two in Humain/Belgium, 4 in Metsähovi/Finland, 8 in Switzerland (5 in Bleien, 1 in Zurich, 2 in Freienbach), 4 in Spain, 5 in Malaysia, 3 in Indonesia (Sumedong, Tomohon and Biak), one in Glasgow/Scotland/UK, one in Peru, one in Kigali/Rwanda, one in Pakistan, 2 in Denmark, one in Japan, one in South Africa, two in Kangerlussuaq/Greenland, 6 in Austria, one in Montevideo/Uruguay, two in Norway, one in Nepal, two in Thailand and two in Ethiopia (Addis Ababa and Mekelle). Through the IHY/UNBSSI and ISWI 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 perform 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. Data from individual instruments are automatically uploaded by FTP to the central server at FHNW. Data which are not locked to UTC (either from the past or from the future) are not automatically archived, they generate an error report.
Instrument deployment including education and training of observers was financially supported by SNF, SSAA, NASA, Institute for Astronomy and ETH Global, formerly known as North-South Center of ETH Zurich and a few private sponsors.

  1. COSPAR Workshop Ethiopia 2018
  2. Raster fly map of the sun with a 5m dish attached to a Callisto spectrometer between 950 MHz and 1260 MHz: contour-plot (4'579KB),  surface-plot (16'023KB). Raster fly map of sky background 12° x 12° (15'357KB)
  3. Ordering link for new Callisto spectrometers from Whitham D. Reeve, Anchorage, Alaska
  4. Ordering link for new Callisto spectrometers, LNA or DISEqC from Christian Monstein, Freienbach, Switzerland. You may also ask for used instruments. Requests for quotation for Callisto instruments and options to cmonstein(at)swissonline.ch with subject = RFQ Callisto
  5. Logos with different background: white  black   yellow1   yellow2
  6. Donations via PayPal to maintain this website and data archive at FHNW are always welcome.
  7. Testsite with L-band LightCurves
  8. Frequency allocation Switzerland at OFCOM

xray   latest  STEREO   
Solar Activity now (courtesy SWPC/NOAA) and GSFC/NASA.

Christian Monstein Christian Monstein is a native of Switzerland and lives in Freienbach. He obtained Electronics Engineer at Konstanz University, Germany. Christian is a SARA member and is licensed as amateur radio operator, HB9SCT. He has 20 years of experience designing test systems in the telecommunications industry and is proficient in several programming languages including C++, IDL and PYTHON. He has worked at ETH-Zürich on the design of frequency agile radio spectrometers, FFT-spectrometers, radio receivers and noise calibration transmitters as payload on a drone. He also has participated in the European Space Agency (ESA) space telescope Herschel (HIFI), European Southern Observatory (ESO) project MUSE for the VLT in Chile. Recently, he was involved in the radio astronomy project 'BINGO' in Uruguay / Brazil and in 'HIRAX' in South Africa. He is still responsible for the hardware and software associated with the e-CALLISTO Project. He plays also the role of a coordinator of SetiLeague in Switzerland and he was also representing Switzerland within CRAF. He is still a member of the ISWI steering committee at UN office for outer space affairs in Vienna (UNOOSA) and has just been nominated as a member of ITU. 

Version: 2019-05-11
Responsible: Christian Monstein cmonstein(at)swissonline.ch