Dark Sky Week 2026
Contributions of the Mathematical-Astronomical Section
International Dark Sky Week (April 13-20, 2026) is a global celebration of the night. From the darkness that supports a restful night’s sleep to the wonder we experience beneath starry skies, the night plays a vital role in our wellness, the well-being of wildlife, scientific discovery, cultural heritage, and more. Yet with the rapid rise of light pollution, we risk losing the natural night we depend on. The time to act is now!
All three talks prepared by the Mathematical and Astronomical Section for Dark Sky Week, in collaboration with the speakers, can be purchased together as a video package. Oliver Conradt's introduction is freely available to everyone.
Math in Movement. How Projective Geometry and Eurythmy Embody the Invisible
Goetheanum in Dornach (Switzerland); June 26-28, 2026.
Workshop with Russell Arnold & Jane Ranck.
Russell Arnold, PhD. Is a Co-Worker in the Section for Math and Astronomy at the Goetheanum. His research in projective geometry spans from applications in the realm of etheric-formative forces to a revival of metamorphic geometry in the mainstream of mathematics.
Jan Ranck is active internationally as a performer, teacher and trainer of eurythmy and eurythmy therapy. She is the founding director of the Jerusalem Academy of Eurythmy and the Jerusalem Eurythmy Ensemble.
The conference language is English only.
The detailed program can be found HERE. Please register by 19 June 2026 via https://goetheanum.ch/en/events/masd26.
Paper on Bud Research
In the framework of the research project Rhythmical Change of Shape in Mistletoe Berries According to Moon and Zodiac Constellations by Renatus Derbidge at the Natural Science Section of the Goetheanum a first paper was published in the open access journal PLOS ONE. It presents methods and software to capture and measure the shape changes of mistletoe berries and leaf buds over time. The paper describes the software used to automatize a number of tasks including contour recognition, optimization of fitting the contour via hill-climbing, derivation of the path curves, computation of Lambda and blinding the pictures for the operator. The validity of the program is demonstrated by results from three independent measurements showing circadian rhythm in mistletoe berries. The program is available as open source and will be applied in a project to analyze the chronobiology of shape in mistletoe berries and the buds of their host trees.
Coauthors of the paper are Linus Feiten (Faculty of Engineering, Chair of Computer Architecture, University of Freiburg, Freiburg, Germany), Oliver Conradt (Section for Mathematics and Astronomy, Goetheanum, Dornach, Switzerland), Peter Heusser (Centre for Integrative Medicine, University of Witten/Herdecke, Witten, Germany) und Stephan Baumgartner (Hiscia Institute, Society for Cancer Research, Arlesheim, Switzerland).