Built in 1970 and located in Gávea by the PUC University, Rio's Planetarium is 16,000 square metres of dedicated star-gazing and solar system-related activities from the highly technical to the most basic and introductory. The Carl Sagan dome is home to a first-rate projection that immerses up to 260 people at a time in the world of the stars (up to 9,000 to be precise), while the smaller Galileu Galilei next door shows some 6,000. Only open to the public at the weekends, midweek the domes are dedicated to school visits and private bookings, and be warned that the air conditioning gets cranked up pretty high so wear something warm.

Elsewhere there is an impressive and mind-bending library of physics, astronomy and, of course, astrophysics-related literature (open Mon-Fri 10am-5pm), a theatre and lecture halls, whilst the Praça dos Telescópios is home to four telescopes that are available for public use on Wednesdays. The permanent exhibition showing a history of astronomy, Número e Cores (Tue-Fri 9am-5pm; Sat-Sun 3-6pm) has some impressive photographs showing the discovery of the phases of Venus, Saturns rings and the obsessive relationship between man and the moon.