The camera for the PAU (Physics of the Accelerating Universe) project has been successfully installed on the William Herschel telescope at the Roque de los Muchachos Observatory on the island of La Palma during the day of June 3rd, has seen its first light that same night and has finished its commissioning today. This instrument is specially designed to measure with precision the distance to galaxies in order to study how the Universe is expanding ever more rapidly under the influence of the mysterious dark energy which makes of 70% of it.