A milestone gathering marking five decades of collaboration and discovery in variable star astronomy.
In April 2025, the European Group on Stellar Observations (GEOS) gathered in Nantes, France, to celebrate its fiftieth anniversary. This in-person meeting marked a long-awaited reunion after the last physical congress in Valencia in 2019 and several years of virtual or postponed events due to the pandemic. Nantes, with its rich history, riverside setting, and the legacy of Jules Verne, provided a vibrant backdrop for the occasion. The conference, organized by Guy Boistel and Jean-François Le Borgne, featured a retrospective on GEOS’s history, scientific talks—including a presentation by Ennio Poretti on the enigmatic RR Lyrae star KIC 2831097—and lively discussions on topics such as smart telescopes, data extraction tools, and the observation of variable stars. The event concluded with a gala dinner in the historic LU biscuit factory, now a restaurant, where members toasted to GEOS’s enduring spirit and achievements.
This milestone congress not only honored GEOS’s innovative approach to variable star observation—promoting both visual and instrumental techniques—but also strengthened the bonds within the international community of professional and amateur astronomers. As GEOS looks ahead to new challenges and discoveries, the group remains committed to advancing stellar research through collaboration, rigorous methods, and the passion of its members.