We looked over the architecturally-interesting Estonian National Museum in Tartu, built atop a former Soviet airfield. Tartu tähetorn | Tartu Old Observatory is Estonia’s first observatory, completed in 1810 and now a museum (📷1). The “pearl” of its collection is Fraunhofer’s refracting telescope (📷2). This instrument was used by German-born Russian astronomer Friedrich Struve to measure how distant stars were, with its superior optics (Fraunhofer was an optician by trade) and a micrometre attachment—a device for calculating angles inspired by cobwebs in the telescope of Gascoigne in 1640 CE. Struve began his famous triangulation survey from the observatory in 1816—subsequently named the Struve Geodetic Arc. Together with two other triangulation points, this undertaking elevates the observatory to the second of Estonia’s UNESCO-listed World Heritage Sites (the other being Tallinn’s Old Town). Angles/ distances were calculated in a chain of 258 linked triangles across 2,810km of the Tartu meridian, passing through 10 countries (Finland, Ukraine, Russia, Belarus, Norway, Sweden, Estonia, Latvia, Lithuania and Moldova). Completing his measurements in 1855, in a blow to flat-Earthers Struve established the size and (🌍 spherical) shape of Earth. The Town Hall and Town Hall Square are the heart of Tartu, seen here from the park on Toomemägi | Toome Hill (📷3). The city is regarded as Estonia’s “intellectual capital” and celebrates this (or risk of infectious mononucleosis?) with a 1998 “Kissing Students” fountain in the square (📷4). The University of Tartu was founded by the Swedish king Gustavus Adolphus in 1632, making it one of the oldest in northern/ eastern Europe. 🇪🇪 #europe #baltics #estonia #eesti 🚀 #travel 🚐 #camperVan #nomad #roadTrip #vanLife 🌍 #unesco