ASTRON is responsible for the operations of the Westerbork Synthesis Radio Telescope (WSRT) and the Low Frequency Array (LOFAR).


The astronomical research at ASTRON is closely aligned with the strengths of our facilities LOFAR and WSRT-APERTIF.


Met onze radiotelescopen nemen wij de meest zwakke signalen uit het heelal waar. Daardoor zijn zij kwetsbaar voor elektromagnetische storing. Met het tijdig treffen van de juiste maatregelen kan storing worden voorkomen.

Wireless Data Lab

Draadloze techniek lijkt vanzelfsprekend, maar de ontwikkeling ervan gaat niet vanzelf. Daarom hebben we bij ASTRON een proeftuin ingericht; het Wireless Data Lab.

Making discoveries
in radio astronomy

ASTRON is the Netherlands Institute for Radio Astronomy, and is part of the Institutes organisation of NWO.
People of ASTRON: Tom Kamphuis

In People of ASTRON we share stories about the people at ASTRON. Who are the people behind the discoveries and innovations and also, who are the people that make sure that everything runs smoothly? Tom Kamphuis is Head Software Delivery and loves that he can contribute to groundbreaking science.

ASTRON lanceert proeftuin voor ondernemers

Om onze kennis over het heelal te vergroten, verlegt ASTRON voortdurend de grenzen van de technologie in haar radiotelescopen. Deze expertise stellen wij nu ter beschikking om de innovatieve kracht van ondernemers te vergroten. Hiertoe lanceren we het Wireless Data Lab (WDL), een proeftuin waarmee ASTRON haar kennis en faciliteiten op het gebied van draadloze dataoverdracht beschikbaar stelt aan het bedrijfsleven en andere instellingen.

ASTRON-led consortium working on SKAO

A consortium led by ASTRON is developing important software components for processing the vast amounts of data that the soon-to-be largest radio telescope in the world will produce.

NenuFAR officially becomes a LOFAR super station

The low-frequency radio telescope NenuFAR will be connected to the international LOFAR telescope, operated by ASTRON, the Netherlands Institute for Radio Astronomy.

Westerbork and the future of GigaHertz astronomy
NWO condemns acts of war in Ukraine – prepares measures
Flurry of new discoveries as incredible new image revealing 4.4 million galaxies is made public
Cosmic flashes discovered in a surprising location in space
Astronomers find largest radio galaxy ever
Looking inside the accretion disc around a supermassive black hole


H2O MegaMaser emission in sources such as the prominent NGC 4258 arise from a thin gas disc surrounding the supermassive nucleus. Space Very Long Baseline Interferometry (SVLBI) experiments with the Russian-built RadioAstron Observatory in Earth orbit and the large Green Bank and Effelsberg telescopes have resulted in the detection of the regularly-spaced emitting clouds inside the disc. The above figure shows a spectrum with a series of H2O emission components obtained with an Earth-space baseline of 19.5 Earth Diameters (about 250.000 km). The upper and lower frames of the above figure show the broad ground-based spectrum and the cross-correlated spectrum of one experiment. The angular resolution of this observation is 11 micro-arcsecs, which corresponds to a footprint of only 62 AU at the host galaxy. The observed molecular emission regions are found to be orbiting inside the rotating disc at a radius of about 0.126 parsec (0.38 lightyears) from the black hole nucleus of the galaxy.

The H2O emission in these regions results from maser-amplification by clouds with excited/pumped water molecules in the foreground as they drift in front of the radio continuum in the nucleus of NGC 4258. The formation of these regions, their regular velocity separation and their time-dependent emission appear consistent with the occurrence of a periodic magneto-rotational instability in the disc. This shear-instability is driven by differential rotation in the disc and is thought to regulate the momentum transfer and viscosity within an accretion disc.

The paper 'Space VLBI Observations of the H2O Megamaser in NGC 4258: evidence for periodic disc instabilities' will be published in Nature Astronomy on 30 June, 2022.

The authors are Willem Baan (XinJiang Astronomical Observatory, CHN, and ASTRON, NL), Tao An (Shanghai Astronomical Observatory, CHN), Christian Henkel (MPIfR, GER), Hiroshi Imai (Kagoshima Univ., JAP), Vladimir Kostenko (AstroSpace Center, RUS), and Andrej Sobolev (Ural Federal Univ., RUS).


Latest tweets

Daily image of the week

On June 13-17, the LOFAR Family Meeting took place in Cologne. After two years LOFAR researchers could finally meet in person again. The meeting brings together LOFAR users and researchers to share new scientific results.

Our renewed ‘Melkwegpad’ (Milky Way Path) is finished! The new signs have texts in Dutch on the one side and in English on the other side. The signs concerning planets have a small, 3D printed model of that planet in their centre.
#Melkwegpad @RTVDrenthe

Daily image of the week

The background drawing shows how the subband correlator calculates the array correlation matrix. In the upper left the 4 UniBoard2s we used. The two ACM plots in the picture show that the phase differences of the visibilities vary from 0 to 360 degrees.

Daily image of the week: Testing with the Dwingeloo Test Station (DTS)
One of the key specifications of LOFAR2.0 is measuring using the low- and the highband antenna at the same time. For this measurement we used 9 lowband antenna and 3 HBA tiles.