Monte Mario Observatory, Astronomical observatory in Monte Mario, Rome, Italy
Monte Mario Observatory, also called Villa Mellini, is an astronomical observatory on the summit of Monte Mario above the right bank of the Tiber in Rome. It has three domes for night observation and a solar tower with a coelostat. It is part of the Observatory of Rome and answers to the National Institute for Astrophysics.
Built in 1923 on the hill of Monte Mario, the observatory was officially opened and equipped with instruments only in 1938, after the closure of the Campidoglio and Collegio Romano observatories. The start of the Second World War halted scientific work until the late 1940s. Its meridian, at 12°27' east of Greenwich, served as Italy's prime meridian for cartography until the 1960s.
The Astronomical Copernican Museum within the facility houses a rich collection of scientific works and manuscripts spanning centuries of astronomy. This collection reflects how different eras understood the cosmos and our place within it.
The location sits on a hillside, so visitors should expect some elevation change and wear comfortable shoes for walking. It helps to check opening hours before visiting, as access may be limited to specific times.
The observatory's meridian, at 12°27′8.4″E, served as Italy's prime meridian for cartography until the 1960s, so Italian maps were referenced to Monte Mario rather than Greenwich. The solar tower, restored in 2009 for the International Year of Astronomy, now hosts guided tours and educational sessions.
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