Ventspils  Radio  Astronomy


Upon withdrawal of the [former Soviet] armed forces from the Baltics in mid-1994, two [formerly military] radio telescopes were handed over to the Latvian Academy of Sciences.  These 32- and 16-meter dishes form the basis of the VIRAC institute, now being developed in international collaboration.

VIRAC  (Ventspils International Radio Astronomy Center)

  In post-cold-war Europe, this is one of very few occasions, where a previously secret military base has been transformed into a civilian research institute.  The preservation of these radio telescopes, and their conversion to civilian use, was at times a quite dramatic process: A.Balklavs: Ventspils Radiotelescopes: History, Parameters, Possibilities, Baltic Astronomy 5, 181-186 (1996).

 


  Geographical location

  The telescopes are some 20 km north of the city of Ventspils, Latvia (some 150 km across the Baltic sea from Sweden; opposite northern Gotland.), some 200 km west from Riga.


The 32-meter antenna

  When left by the armed forces in 1994,  the antennas had no functional electrical systems, and there was no technical  documentation.  Groups from different Latvian institutes (Institute of Astronomy, Institute of Physical EnergeticsRiga Technical University, and others) spent considerable efforts to experimentally determine the antenna properties, and then to gradually restore its various functions.  The first movement of the 32­meter dish was achieved in May 1995, and the first test observations of celestial sources followed.  During 1997, optical encoders were installed at both telescope axes, and a computerized pointing and tracking system was put in operation during 1998, supported by grants from the Latvian Council of Science, and The Royal Swedish Academy of Sciences.


Early observations

  Test observations during 1997 of sources such as CasA and TauA at 11 GHz (2.7 cm wavelength) verified the quality of the antenna surface also for shorter wavelengths, and it is believed that the 32­m antenna will be usable down to about 1 cm.


Solar activity

  Solar observations at 11 GHz: This radio image shows several active regions.


First VLBI observations

  The first observing campaign in very long baseline interferometry took place in November 1999, as part of the Low-Frequency VLBI Network, connecting radio telescopes across Europe and Asia.  Mark II electronics were used for measurements at 327 MHz.


The 16-m antenna

  Work is currently in progress to put also the smaller 16-m antenna into operation, with a view towards applications in space communication and remote-sensing applications.


GPS receivers

  On the VIRAC site (some 200 m from the 32­m antenna), a GPS receiver is operated, providing data for both geophysics and VLBI experiments.  Absolute gravimetry measurements have also been made.


   International cooperation in radio astronomy

  In February 1996, an agreement on cooperation in radio astronomy was signed in Stockholm, involving The Royal Swedish Academy of Sciences (KVA),  VIRAC (through the Latvian Academy of Sciences), Onsala Space Observatory  in Sweden,  and Russian space science institutes, represented by the KOSMION organization.  The aim was to support the development of VIRAC radio astronomy, and foster international collaboration, in particular concerning Very Long Baseline Interferometry (VLBI).  A Scientific Advisory Council was set up, charged with establishing programs for the scientific work.  Swedish representatives on this council were Roy Booth (Onsala) and Dainis Dravins (KVA; chairman).

  The first meeting of the VIRAC Scientific Advisory Council was held in Riga and Ventspils in November 1996,  the second in June 1998, the third in April 2000, and the fourth in May 2002, involving participation from Latvia, Sweden, Russia, Estonia, and the Netherlands..

  In July 2001, Ventspils University College and VIRAC hosted "Radio Universe", The 2001 Nordic-Baltic Summer School in Radio Astronomy, an intensive two-week course for some 30 graduate students from the Nordic-Baltic region, involving 18 lecturers and instructors from also elsewhere in Europe.  Besides lectures and exercises at Ventspils College, all students made observations of the Sun at 2.7 cm (11 GHz) using the 32-meter VIRAC antenna, and presented their analyses at the end of the course.


European collaboration in radio astronomy:

   


Comments are welcome to dainis@astro.lu.se

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