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.

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.

This dissertation presents the results of the importance of creativity for ICT-students of Dutch universities of applied sciences (in Dutch: hogescholen), and the functioning of training courses that aim to promote creative abilities is highlighted.

BplusC Libraries and Old Observatory Leiden working together to provide telescopes

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 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 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.

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.

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.

Wordt het nog wat met de Arabische lente?

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…

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,…

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.

By carrying out fundamental research and providing excellent education, universities become a breeding ground for innovation and entrepreneurship.

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…

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.

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…

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

What did we do over the past year? Well, we played quantum games, helped develop an instrument for the Extremely Large Telescope and started a new bachelor's programme. Oh, yeah, and we officially opened our brand new Gorlaeus Building! Warm up the fingers and get ready to click and scroll through…

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…

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.

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.

The Leiden Science Young Talent Award celebrates a student who completed their bachelor’s degree with an outstanding thesis.

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).

One of the key discoveries in exoplanet research over the past decade is the abundance of small planets in our Milky Way. Despite their high numbers, our understanding of their atmospheres remains limited, and it is unknown if they possess atmospheres at all.

To strenghten ties with the public, press, other academics and wider society, LION employs an outreach officer.

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.

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…

This research focuses on the distribution of chemical elements in protoplanetary disks, the birthplaces of planets. These disks form around young stars and contain gas and dust, from which planets grow. Ice plays a crucial role in planet formation, aiding the clumping of dust particles and influencing…

The ability to collect and interpret huge quantities of data has become indispensable to society and academia. Leiden University is a knowledge and expertise centre for data science that places the emphasis on interdisciplinary collaboration and innovation.

The Leiden Science Young Talent Award is awarded yearly to a student who completed their bachelor’s degree with an excellent thesis.

The We Are Science Week, inspiring lectures, and enjoyable gatherings. This year, we frequently came together to inspire and connect with one another. Our biggest event took place at the start of the academic year in September: the official opening of our new Gorlaeus building.

Principles of Environmental Sciences provides a comprehensive picture of the principles, concepts and methods that are applicable to problems originating from the interaction between the living and non-living environment and mankind. Both the analysis of such problems and the way solutions to environmental…

Research truly comes to life when it contributes meaningfully to society. By sharing our findings, advising policymakers or contributing to community projects – we can make a real impact. Scroll down and discover how Science and society can mutually benefit from each other.

From the largest numbers to the smallest molecules and from the oldest galaxies up to the latest algorithms, explore our standout discoveries and most inspiring collaborations from the past year!

The CS-NL network is a vibrant and active community of Citizen Science practitioners, initiators, researchers and participants from across all corners of society (Academia, Industry, Government, Civil Society, and Citizens) who come together to share knowledge and know-how for participatory research…

Is it possible to formulate a new conceptual foundation for attributing an evaluative role to historiography of science, without relinquishing the historiographic sensitivity of recent work in the discipline?

How can we bridge the gap between experts and the general public?

The overall objective of ECS is to widen and strengthen the European Citizen Science community through capacity building and awareness raising activities such as the creation of a European Citizen Science Academy and the establishment of a network of 28 ECS Ambassadors.