Civic Planetarium Ulrico Hoepli,
Designed by the architect Piero Portaluppi and built in less than a year within the public gardens of Porta Venezia, the Planetarium was inaugurated on 20th May 1930. The institution was donated to the city by Ulrico Hoepli, a Swiss publisher who moved to Milan, and who, already by the end of the nineteenth century, was recognised for his numerous technical and scientific publications. The shape of the building, reminiscent of an archaic and severe classicism, and the materials employed, ceppo di Albino and marble from Crevola d’Ossola, make it one of the most original and representative architectural works built in Milan between the two world wars. An architecture that, in its skilful and eccentric juxtaposition of pure shapes and in its contemplation of the past, authentically represents the monumental motive, enhanced by the central plan and the classic atrium and hall sequence. The building is dominated by a large hemispherical dome which is almost 20 m in diameter and coated externally in copper. On the inside of the dome, a planetarium instrument projects images of the constellations and the celestial vault. A continuous silhouette of the City of Milan is engraved around the room, along the entire inside base of the dome, reproducing the Milanese skyline at the beginning of the thirties: the Duomo, the Galleria and many other monumental buildings of the city can be identified, while two icons of Milanese architecture, the Velasca Tower and the Pirelli Tower are not illustrated, since they had yet to be built at the time of the dome’s creation. The planetarium has an overall capacity of 375 seats on sturdy Thonet chairs arranged in a circular and concentric pattern. The chairs, which are for the main part original pieces, are fitted on rotating bases, enabling viewers to observe the projections inside the dome from any point: the effect obtained is that of an illusion show in which spatial references are lost, where the walls give way to the dynamics of the silent movement of the stars. Outside, a short flight of entrance steps lead up to a pronaos with four baseless ionic fluted columns supporting an elegant tympanum and evoking the image and character of a classical temple. The dome, of striking figurative impact, emerges from an octagonal volume that defines the building’s perimeter within the gardens. The idea of a Planetarium in Milan originated after the establishment of the Planetarium of Rome in 1928, the first to be built in Italy. During the construction of the Milanese building, the astronomer Emilio Bianchi, director of the Brera Observatory, collaborated as head scientist, in a sign of continuity that has seen Milan excel in astronomical studies since the eighteenth century. The Planetarium, which is considered to be one of the places of excellence for the dissemination astrophysics and astronomy, has been renovated several times after the second world war. In 1968 the old model II Zeiss optical-mechanical planetarium instrument was replaced with a model IV version, which is still in operation today. In the nineties a multimedia projection system was installed to support the instrument. This system has since been further enhanced, in order to obtain greater versatility at conferences, scientific seminars and in the programme of events.