The Old Observatory houses four historical telescopes. On this page you can learn more about them.

Our current research focusses on the exploration of the Universe using the neutrino. This neutral, almost massless and only weakly interacting particle can open a window to the distant Universe and also dense regions from which photons cannot escape.

The design for the METIS instrument for the Extremely Large Telescope (ELT) is final. The European Southern Observatory (ESO) has given the green light for production of all parts of the instrument. It is the first ELT instrument, designed and to be built under Dutch leadership, to formally pass the…

After nearly 70 years, the Leiden Observatory has a new telescope. A crowdfunding action in March brought in the 20,000 euros required to build a solar telescope. On 19 September Rector Magnificus Carel Stolker officiated at the opening.

Leiden scientists will be working on the development of a camera for the European Extremely Large Telescope that is currently under construction. On 28 September the Netherlands Research School for Astronomy signed an agreement with the European Southern Observatory.

To what extent does exoplanet Proxima b resemble our Earth? And is there some form of life present? Astronomers hope to find answers to these questions with the new European Extremely Large Telescope (ELT). An NWO research grant of €18 million will allow a Dutch consortium to continue building instruments…

Director General of ESO, Tim de Zeeuw received President of the Republic of Chile, Michelle Bachelet Jeria for a ceremony marking the first stone of ESO’s Extremely Large Telescope (ELT).

Promotor: J.N. Kok, Co-promotor: M.S. Lew

Even though more than 4000 extra-solar planets are known today, only a small fraction of these has been captured in an image. To better understand the planet formation mechanisms in solar-like environments we started the Young Suns Exoplanet Survey (YSES).

BplusC Libraries and Old Observatory Leiden working together to provide telescopes

The alignment of the James Webb Space Telescope is complete. The space observatory is able to capture sharp, well-directed images with each of its four powerful scientific instruments on board. The MIRI instrument, on which Professor of Molecular Astrophysics Ewine van Dishoeck also worked, was the…

The 'deepest and sharpest' image of the Universe to date: the first photos from the new James Webb space telescope yesterday mesmerised astronomers and the public alike. Leiden Professor of Molecular Astrophysics, Ewine van Dishoeck, spoke to various media outlets about the first images, which include…

After a period of maintenance, the 'Photographer' telescope is available once again for visits at the Old Observatory.

After a period of maintenance, the 'Photographer' telescope is available once again for visits at the Old Observatory.

Large-scale computing infrastructure, such as supercomputers, cluster, and clouds, are already pervasive, most members of our society interact with them daily: social networks, government services, media streaming services--all systems heavily interfacing with the members of our society--are powered…

This thesis examines silicon pore optics (SPO), a technology that exploits silicon wafers from the semiconductor industry to create extremely high quality X-ray optics, by studying its manufacturing process, applications, and prospects.

Meet the newest Full Professor at the Leiden Observatory: Joe Hennawi. All the way from Santa Barbara, California, Hennawi will strengthen the astronomy institute. In Leiden, he will use his recent ERC Advanced Grant to study how supermassive black holes come into existence.

In navolging van Duitsland en het Verenigd Koninkrijk, wil de ministerraad een nieuw wetsvoorstel, om verheerlijking van terrorisme en steunbetuiging aan terroristische organisaties strafbaar te stellen. Wim Voermans, hoogleraar Staatsrecht, duidt de zaak in Dagblad Trouw.

Het kabinet is voornemens om het strengste asielbeleid ooit te gaan voeren. In het NRC geven Peter Rodrigues (emeritus hoogleraar immigratierecht) en Mark Klaassen (universitair docent immigratierecht) commentaar op dit voornemen.

A study into the investment and impact of construction projects on Mycenaean communities in Late Bronze Age Greece

An in-depth history of Large Language Models—and what their ubiquity, disruption, and creativity mean from a wider sociopolitical perspective.

The Old Observatory in Leiden has reclaimed its most important telescope. Since the 1960s, the Meridian Circle (also known as a transit telescope) had been housed in the Boerhaave Museum. After more than sixty years, the telescope is finally back in its original location. Now, the public can enjoy it…

Promotores: F.H.J. Redig, W.T.F. den Hollander

After 25 years, December will finally see the launch of the long-awaited James Webb space telescope. Leiden astronomers are watching with great excitement: not only were they involved in the construction of important instruments on board, the telescope will also reveal many new secrets of the universe,…

ESA’s space telescope Gaia, which maps the Milky Way, completes its active phase of scanning the sky on 15 January. Over the past decade, Gaia has made more than three trillion observations of about two billion stars and other cosmic objects. ‘Gaia is already the discovery machine of the decade,’ Leiden…

On Monday 9 May Mercury will pass between the Earth and the Sun. This rare event can be followed in the Leiden Observatory. The Observatory's new solar telescope produces a very clear image and offers a unique opportunity to observe Mercury at the highest magnification possible in the Netherlands.

Paul Hudson, Associate Professor of Physical Geography at Leiden University College, examines human impacts on lowland rivers in his new book.

Astronomers at Leiden University have discovered the first planets using a new instrument: the planet hunter MASCARA. This instrument, developed at Leiden Observatory, looks specifically for planet transitions around the brightest stars in the sky, which surprisingly enough have so far have hardly been…

Until the 1990s, the only known planets were those in our Solar System. Three decades later, several thousand exoplanets have been discovered orbiting stars other than the Sun, and substantial efforts have been made to explore these strange new worlds through spectroscopic analyses of their atmosphe…

After 25 years, this December will finally see the launch of the long-awaited James Webb space telescope (JWST). Leiden astronomers are watching with great excitement: not only were they involved in the construction of important instruments on board, but the telescope will also reveal many new secrets…

No joke: on 1 April, the antique Van de Wall telescope was relocated to the atrium of the Gorlaeus Building. Have you spotted it yet?

De rol van de Eerste Kamer is het toetsen van wetten op uitvoerbaarheid. Wim Voermans, hoogleraar Staatsrecht, zegt voor NPO Radio1 dat de Eerste Kamer nu te veel een politieke rol in plaats van een controlerende rol vervult.

Oberon Janszen, alumnus Bestuurskunde, ging na zijn studie als stagiair bij de Inspectie der Rijksfinanciën aan de slag

For the first time in over half a century, one of oldest telescopes at the Leiden Observatory is getting a major improvement.

The Leiden astronomer Huib van Langevelde) has been selected as the new director of the Event Horizon Telescope (EHT). The EHT is a collaboration involving about 350 scientists from 18 countries. It combines the ALMA array in Chile with sub-millimeter telescopes around the world and published the first…

For the first time more than half century, one of oldest telescopes at Leiden Observatory is getting a major improvement.

Even with state-of-the-art technology, it is almost impossible to see: a cosmic neutrino. Yet scientists have managed to image this particle with a deep-sea telescope. And that could help to better understand our universe. Leiden particle physicists collaborated on this ambitious project, published…

Leiden scientists and companies receive 1.37 million euros to develop technology for the Einstein Telescope. This underground telescope will measure gravitational waves and must therefore be extremely sensitive. To that end, the consortium conducts research on the damping of vibrations at temperatures…

Everyone wherever they are in the world can follow free online academic courses offered by Leiden University.

The Netherlands Organisation for Scientific Research NWO allocates nearly € 19.5 million to a Dutch cluster that contributes to the development of an X-ray camera and spectrograph for the new European space telescope Athena. Leiden Observatory is one of the members of the cluster.

Astronomers from, among others, SRON and Leiden Observatory have discovered long-sought intergalactic gas with ESA’s space telescope XMM-Newton. This gas is one of the pieces of the puzzle to map the total amount of ‘normal’ matter in the universe. The research will be published in Nature on 21 June…

The strangest things come out at night. This is the motto of the Leiden Museum Night due to take place on 28 May. Leiden University is once again playing a key part.

How do stars and galaxies form? What is dark matter? To answer these and other questions, we need increasingly large telescopes. And to build these, we need international partnerships. A series on the impact of collaboration.

Scientists have detected a neutrino with the highest energy ever measured. Leiden physicists Maarten de Jong and Dorothea Samtleben were involved in this project, which was widely covered in newspapers and online media last week.

KM3NeT is selected as one of the ten top research facilities in NWO’s National Roadmap for Large-scale Research Infrastructure. Leiden physicist Dorothea Samtleben is the deputy program leader of Nikhef’s KM3NeT group.

Three Dutch-Belgian telescopes have started operating at the ESO La Silla Observatory in Chile. This so-called BlackGEM array will scan the southern sky to hunt for cosmic events that produce gravitational waves, such as mergers of neutron stars and black holes. Leiden astronomer Rudolf le Poole is…