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Solar telescope officially unveiled in Old Observatory

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.

Sunshine after the rain

The ceremony started early. During a shared breakfast, Stolker welcomed the guests. This was followed by short speeches by astronomer Frans Snik and Leiden Professor of Molecular Astrophysics Ewine van Dishoeck. Heavy rain fell during the unveiling of the solar telescope, but later then sun came out and people were able to watch a projection of the Sun.

Studying sunspots

Rector magnificus Carel Stolker nam de zonnekijker officieel in gebruik.


What is remarkable about the Sun is that it is the only star we can study in detail, commented Snik. The Sun often displays sunspots, dark areas on the surface of the Sun that turn with the Sun’s rotation. Our current telescope observations of sunspots are intensifying, not only because it is unclear how these spots are formed, but also because sunspots can lead to sun flames and sun storms, phenomena that impact life on earth. These explosions on the surface of the Sun can paralyse our cars’ satellite navigation systems, disturb air traffic, and even overtax our electricity network.


On 19 September, the KNAW Astronomy and Art exhibition will open in the visitors’ centre of the Old Observatory. The exhibition has been made possible thanks to Ewine van Dishoeck: ‘Science and art go hand in hand. They mutually inspire one another. The exhibition clearly shows the versatility with which art can represent the universe.’ The exhibition runs until 2 October.

Unique collaboration

Toen de zon doorbrak konden de aanwezigen de zonnekijker direct uitproberen

The first solar telescope, the heliostat, was introduced in Leiden in 1742. Thanks to a moving mirror, the Sun could be projected on a fixed location. The crowdfunding action has allowed for a unique collaboration in which the Leiden Observatory Workgroup and the Leiden Instrument Makers School were once again able to build a heliostat. As of 18 October, in fine weather you can watch the Sun live in the visitors’ centre of the Old Observatory.


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