LOFAR in a nutshell

  The LOw Frequency Array, or LOFAR for short, is a digital radio telescope that spans several European countries with its core in the Netherlands. LOFAR leads the way for a new generation of digital radio interferometers that consist of a multitude of antenna fields spread over large distances. The radio waves that are received by thousands of antennae are sampled digitally, the signals are transmitted over large baselines via high-speed (10 Gb/s) fibre cables to a high-performance computing facility, where the radio images are synthesized in real time. This way, LOFAR acts like a huge digital camera that scans the entire sky in very low radio frequencies. LOFAR opens up a new window to the Universe by observing at very low radio frequencies (10 - 240 MHz). In this range of frequencies the sky is largely unexplored. Here LOFAR offers unprecedented angular resolution and sensitivity and, thus, promises new discoveries and exciting science. Moreover, LOFAR is also an important scientific and technological pathfinder for the next generation of radio telescopes, the Square Kilometre Array (SKA). The SKA will be the world's premier imaging and surveying telescope with a combination of unprecedented versatility and sensitivity that will be a ~600 Mio. Euro project.

LOFAR Core Station
LOFAR was developed by a consortium of institutes, universities and industrial parties, led by ASTRON, the Netherlands Institute for Radio Astronomy. The heart of LOFAR lies in the northeast of the Netherlands and spreads over several European countries. The LOFAR core has 24 stations, which are complemented by 14 remote stations in the Netherlands. Thirteen international stations in Germany (6), Poland (3), France (1), Ireland (1), Sweden (1) and United Kingdom (1) are currently operational. 
 
With LOFAR, astronomers will get a glimpse at the epoch of formation of the very first stars in the universe, they will explore extragalactic magnetic fields, chart millions of galaxies, monitor solar activity and search for extrasolar planets.
  
In collaboration with the University of Bielefeld, Hamburger Sternwarte constructed a LOFAR Station in Norderstedt, close to the City of Hamburg, which is in operation since 2015.
 
LOFAR stations consist of fixed antennas that have no moving parts. The whole array is made up of about 50 stations, each roughly as big as a football field. Each LOFAR station has two separate arrays of antennas. These are referred to as the Low-Band Array (LBA) and High-Band Array (HBA). The LBA is optimised for the frequency range 30–80 MHz and the HBA for 120–240 MHz. The gap between the two bands is where FM radio is broadcast. Phased arrays such LOFAR work by exploiting the physical effects of constructive and destructive interference. By adding phase delays between the signals received at every single antenna, the telescope can me made most sensitive in on particular direction of the sky. This so-called beam can be steered electronically across the sky. The signals from all station are "synthesized" into images in one big supercomputer that is located in Groningen (NL).