dual-dipole antennas (the equivalent of a full LOFAR station) are grouped in four clusters, the central cluster with 48 dipoles and other three clusters with 16 dipoles each. Each cluster is about 100 m in size. The clusters are distributed over an area of ~500 m in diameter. In November 2007 the first international LOFAR station (DE601) next to the Effelsberg 100 m radio telescope became the first operational station. The first fully complete station, (CS302) on the edge of the LOFAR core, was delivered in May 2009, with a total of 40 Dutch stations scheduled for completion in 2013. By 2014, 38 stations in the Netherlands, five stations in Germany (Effelsberg, Tautenburg, Unterweilenbach, Bornim/Potsdam, and Jülich), and one each in the UK (Chilbolton), in France (Nançay) and in Sweden (Onsala) were operational. LOFAR was officially opened on 12 June 2010 by Queen Beatrix of the Netherlands. Regular observations started in December 2012. See also ASKAP: Australian Square Kilometre Array Pathfinder Long Wavelength Array (LWA) LORUN: LOFAR at Radboud University Nijmegen MeerKAT: Karoo Array Telescope Murchison Widefield Array (MWA) Precision Array for Probing the Epoch of Reionization Ukrainian Low-Frequency T-shaped Radio Telescope Giant Metrewave Radio Telescope References External links LOFAR website LOFAR national sites: Germany – UK – Sweden – France – Poland – Ireland – Finland ASTRON website Surveys Key Science Project Transients Key Science Project Epoch of Reionization Key Science Project Solar Physics & Space Weather Key Science Project Cosmic Magnetism Key Science Project Interactive map of possible station locations A guided tour of the LOFAR-UK station LOFAR as a Probe of the Sources of Cosmological Reionisation. (preprint: astro-ph/0412080) LOFAR, a new low-frequency radio telescope. (preprint: astro-ph/0309537) LOFAR: A new radio telescope for low-frequency radio observations: Science and project status. (preprint: astro-ph/0307240) Square Kilometre Array (Scholarpedia article). Das Square Kilometre Array (in German), reprint from Sterne und Weltraum 9/2006. mpifr-bonn.mpg.de Buildings and structures in Drenthe Interferometric telescopes Radio telescopes University of Groningen Borger-Odoorn