Galilean moons century when other inner moons were discovered, and Marius' names became widely used. Galileo was able to develop a method of determining longitude based on the timing of the orbits of the Galilean moons. The times of the eclipses of the moons could be precisely calculated in advance, and compared with local observations on land or on ship to determine the local time and hence longitude. The main problem with the technique was that it was difficult to observe the Galilean moons through a telescope on a moving ship; a problem that Galileo tried to solve with the invention of
Vila do Conde than 20 metres) disappear north of the Ave River. Yet, these deposits are irregular, and most comparable sediments are not necessarily found at the same altitude. There are also deformations associated with the last inter-glacial period, that have affected these sedimentary layers, most commonly in the beach of Sampaio, where deposits have been discovered between various altitudes (5 and 9 metres). The municipality is subdivided into the following local government civil parishes, of which Azurara, Árvore and Vila do Conde form the urbanized city of Vila do Conde: Vila do Conde is twinned with: The municipal authorities have promoted a