Royal Netherlands Astronomical Society / Koninklijke Nederlandse Astronomenclub

Nynke Visser

Dutch Astronomy: The Next Generation

I'm Nynke, a PhD student at the Kapteyn Astronomical Institute and the project manager for DARKER SKY. Alongside my research, I’m passionate about public engagement and science education.

DARKER SKY is an Interreg North Sea project dedicated to reducing light pollution to enhance biodiversity and ecological connectivity across the North Sea region. We work with municipalities, communities, and experts across disciplines, like astronomers, ecologists, sociologists, and policymakers, to explore how artificial light at night impacts both people and ecosystems. Our goal is to create practical routines and guidelines that help cities reduce light pollution without compromising the feeling of safety or usability.

A central part of our research is improving how we measure sky brightness. The graph shows an example of measurements taken at the two telescopes operated by the Kapteyn Institute: one at the Blaauw Observatory on the Zernike Campus in Groningen, and another in the Dark Sky Park Lauwersmeer. The graph compares the sky brightness at both telescope locations during the night of 18 to 19 May 2025. The data was sourced from www.washetdonker.nl and recorded using a Sky Quality Meter (SQM).

Using the average of the 10% darkest measurements, the sky brightness at Zernike Campus was approximately 19.7 mag/arcsec², while at Lauwersmeer it reached 21.6 mag/arcsec². According to the empirical relation described in Cinzano, Falchi & Elvidge (2001), these values correspond to a limiting naked-eye magnitude of about 5.3 for Zernike and 6.9 for Lauwersmeer. This means that under these conditions, an observer in Zernike could see about 2,500 stars with the naked eye, while in Lauwersmeer, this number can rise as high as 7,000 stars.

Dutch Astronomy: The Next Generation

Dutch Astronomy: The Next Generation features our PhD Student and PostDoc Members and their work, while they also take over our social media to illustrate the community of Dutch Astronomy!

Check out all of the page links at: https://www.kna-rnas.nl/community/the-next-generation