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Open Day 2018

Sunday 28 October 2018
Parking on the grounds of the Old Observatory is prohibited.
Oude Sterrewacht
Sterrenwachtlaan 11
2311 GW Leiden

On Sunday October 28, the annual open day of the Old Observatory will take place. During this day everyone can visit the Old Observatory for free and enjoy activities in the historic building.

The doors open at 12:00 and close again at 17:00. Visitors can participate in various activities from children's workshops and planetarium shows to lectures and quizzes; for young and old there is something fun to do.

Below you will find the full program for the open day.

Book Presentation "Wandelen tussen de Sterren in Leiden" (Dutch)

Jos van den Broek. Start: 14:00 in the Kaiserzaal.

In many places in Leiden you can see that man has always been fascinated by celestial phenomena: from ancient Egyptians in the museum of antiquities and Balinese and Aztecs in the museum of ethnology to Gerrit Dou's astrologer in De Lakenhal. More recently Einstein and De Sitter discussed the stars and Oort, Van de Hulst and Mayo Greenberg made important discoveries. Leiden research in physics and astronomy is also world-class now, with scientists such as Ewine van Dishoeck, Jan Zaanen, Carlo Beenakker, Xander Tielens and Marijn Franx. A scientific walk along physics and astronomy can therefore rightly be called 'walking between the stars'.

For half a century now, Leiden native Jos van den Broek has been amazed at the countless scientific and cultural treasures that Leiden has to offer. Earlier, the now emeritus professor of scientific communication wrote the book 'From Albinusdreef to Zeemanlaan - A scientific walk along Leiden streets, buildings, museums and institutes'. By his hand now appears 'Walking among the stars - Physics and astronomy in Leiden, then and now', which will appear on Sunday October 28 during the open day of the Old Observatory. The booklet contains a physics walk, an astronomy walk, an astrocultural walk and a sundial walk. The walks (and a bike ride) take the reader past the Old Observatory, the Academy Building, the wall formulas, the Leiden museums and the Leiden Bio-Science Park.

The first copy of 'Walking among the stars' will be presented to Prof. George Miley, spiritual father of Universe Awareness. Jos van den Broek will then tell about his own most special 'discoveries' that he has included in the walking guide.

Lecture SPICA and Herschel (Dutch)

Peter Roelfsema. Start: 15:00 in the Kaiserzaal.

Herschel and SPICA are two important observatories in a long Dutch tradition of infrared space research. As in previous IRAS and ISO missions, SRON played a leading role in enabling the Herschel satellite, which was launched in 2009, to carry out interesting studies, for example, into the role of the various processes that produce stars and which substances and molecules are important in this respect. Together with a large international consortium for Herschel, SRON supplied the HIFI instrument. HIFI was unique in being able to determine the exact chemical fingerprints of substances that are important in star formation.

The next step in far infrared research will be taken with SPICA, a space observatory with an extremely cold and therefore very low radiation telescope. Together with another international consortium, SRON is building the far-infrared spectrometer SAFARI for SPICA. By combining SRON's ultra-sensitive TES detectors with the low background radiation level of SPICA's extremely cold telescope, SAFARI will be able to detect one hundred to one thousand times weaker sources than previously possible. This will make it possible to trace the history of star and galaxy formation and evolution back to the earliest stages of the creation of the universe.

SRON senior scientist/project manager Dr. Peter Roelfsema is the Principal Investigator for SAFARI, the largest European instrument for the SPICA infrared space telescope. He is also scientific leader for the SPICA mission, which is currently being developed as a joint ESA-JAXA project, for launch around 2030.

Astronomy on Tap (English)

At 13:00 and 16:00 in the Kaiserzaal.

Astronomy on Tap brings professional scientists to a bar in Leiden for informal and simple astronomy-related talks, in English. For the second year in a row, they will be bringing their usual program to the Old Observatory! Each of the two sessions will include a short talk, followed by an exciting pub quiz! If you do well, you might go home with some awesome prizes.

At 13:00 Themiya Nanayakkara will tell us why challenging ourselves to explore the Universe is rewarding in many different ways. Every year we spend billions of Euros on trying to understand the unknown and through our ventures to the far away mysterious Universe, we have contributed in many ways closer to home. Themiya will discuss how rocket science has influenced our everyday lives.

At 16:00 Roohi Dalal will tell us all about the expansion of our Universe. From its history all the way to the (relatively) recent discovery of its accelerated expansion. She will explain the way astronomers measure the expansion rate, and the implications that these measurements have on our understanding of fundamental physics.

SRON And Modern Research

Room C002.

Last year the papers were signed to move SRON Netherlands Institute for Space Research from Utrecht to Leiden. On the open day a number of models and animations of projects developed by SRON for modern research will be shown. There will also be a number of Leiden astronomers to answer questions. Come by for a look or a good conversation about astronomy!

Escape Room

Starts every 20 minuten. Takes 15 minutes. Signup at the entrance of the escape room mandatory!

Can you escape from the telescope's cellar? Take on the challenge with a minimum of two and a maximum of six people! Solve as many riddles as possible within 15 minutes to find the way out...


Starts every half hour. Takes 30 minutes. Location: C-wing. Reservation at the reception mandatory!

Due to the amount of light pollution in the Netherlands it is very difficult to see many objects in the sky at night. But not during the open day! Take a journey in our planetarium through time and space to distant planets, nebulae and maybe even black holes!


Starts every 20 minutes. Takes 30 minutes. Location: C-wing. Reservation at the reception mandatory!

Are you curious what secrets and anecdotes are floating around in the hidden of the Old Observatory? Then let yourself be guided by an astronomy student! Each tour includes a visit to one telescope.

Light Lab

Visitor center.

Looking at stars involves more than just pointing a telescope. Light has all kinds of interesting and sometimes crazy properties that we have to take into account. Come and see the Light Lab to see what kind of effects light can cause.

Children's activities

Meridian Lounge,

What could aliens look like? How do you build a good satellite? These kinds of questions keep the smartest astronomers busy every day. But that doesn't mean you can't think along! In the children's corner you can try to come up with a solution for these problems yourself.

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