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.

BplusC Libraries and Old Observatory Leiden working together to provide telescopes

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.

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.

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.

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…

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.

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…

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.

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.

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

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).

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…

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.

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

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.

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.

Rychard Bouwens from the Leiden Observatory is the first scientist in the Netherlands to be assigned a Large Programme on the state-of-the-art ALMA telescope in Chile. With his team, he wants to use the unique capabilities of the billion-euro facility to investigate the build-up of massive galaxies…

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,…

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…

Astronomers at ASTRON and Leiden University have used the LOFAR radio telescope to discover a 'brown dwarf' – a faint object more massive than Jupiter, but significantly less massive than the Sun. The discovery of the object dubbed Elegast, opens up a new path that uses radio telescopes to discover…

No more lectures and exams for the Radio Astronomy course taught by Michiel Brentjens. The corona crisis is a moment of reflection that has changed his whole way of teaching. Instead of being in front of the class, he lets his students build a radio telescope with paint cans.

Astronomer Ignas Snellen studies exoplanets using telescope observations. But how is that possible when all the big telescopes are more or less at a standstill? Luckily, he has contact from home with a robot telescope in Mexico and his WIFI is finally working well.

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).

How can you see something that’s invisible? Well, with Euclid! This future ESA telescope will map the structure of the Universe and teach us more about invisible dark matter and dark energy. Scientific coordinator of Euclid and Leiden astronomer Henk Hoekstra explains how this works.

This thesis describes the Multi-site All-Sky CAmeRA (MASCARA), which consists of two small robotic telescope designed to detect exoplanets around the brightest stars in the sky.

The Leiden Observatory is starting a crowdfunding campaign to raise enough money to construct a new telescope.

The Werkgroep Leidse Sterrewacht (WLS) is an amateur association that, in addition to organising public activities, is also heavily involved in maintaining the historical telescopes in the Old Observatory.

An international team of astronomers that includes researchers from Leiden has discovered the most distant galaxy yet. The galaxy, called EGS8p7, is 13.23 billion light years away from Earth and already existed when the universe was only 550 million years old.

The LOFAR radio telescope produces petabytes of data every year. Radio Astronomers use complex multi-step pipelines to process this data and produce scientific images.

Visitor Center Old Observatory Leiden The Old Observatory of Leiden is the oldest extant university observatory in the world. While students of Leiden University receive lectures in the main part of the building, the visitor center in the basement and the telescopes on the building serve the general…

Emiel Por is our Leiden Observatory's nominee for the C.J. Kok Jury Award 2020.

What is neutron star matter?

Large telescopes can look so deep into the Universe that they can also look back billions of years in time. From 2018, the successor of the Hubble Space Telescope, the James Webb Space Telescope, will be able to see the period just after the Big Bang, when the first stars and galaxies formed. Astronomers…

Astronomers want to understand the Universe, from the Big Bang to the present day, and what the future will hold. In Leiden they focus on two key questions: ‘How did stars and planets originate’ and ‘How were galaxies and black holes formed in the young Universe?’ A new generation of telescopes – just…

The METIS instrument that’s being built for ESO's future Extremely Large Telescope (ELT) in Northern Chile under the leadership of the Dutch Research School for Astronomy (NOVA) has reached an important milestone: the preliminary design has been approved.

Astrophysicist Ewine van Dishoeck has been awarded an honorary doctorate from the University of Geneva. She received the award on 11 October during the Dies academicus of the Swiss university, which, like Leiden University, is part of the European research university federation LERU.

Are there other planets like the earth, and will there also be life? Astronomers study planets around stars other than the sun, with the aim to find out what kind of gasses their atmospheres are made up with.

Promotor: M. de Jong, Co-Promotor: Samtleben

On this section of the website you can find more information about the Old Observatory and the current astronomy research institute.

The Old Obervatory Leiden is one of the partners of the local learning ecosystem ‘Verwonder om de Hoek’, an educational platform from Leiden that lets school children and families wonder about the world of Nature, Science, Technology and Sustainability. On this page you will find the educational programmes…

Every month there is an opportunity to visit the Old Observatory in the evening. These open evenings consist of a lecture followed by a visit to the telescopes in the building.

The first photo of a black hole and measuring anxiety in the brain... From 13 until 22 May we're serving a free slice of science with your pizza.

With each discovery that is made, the universe reveals a fraction of its secrets: the most distant galaxies and quasars, the atmosphere of exoplanets, evidence of dark matter, complex molecules in space. This is what fills the days and nights of the researchers from the Leiden Observatory and their…