Complejo Astronómico El Leoncito

This desert observatory in the Parque Nacional El Leoncito is open for daytime visitors, who can step inside and learn how Argentina’s most powerful telescope, the 2.15m Telescopio Jorge Sahade, works on a 40-minute tour, which departs from the visitor center almost every hour on the half hour and requires no advanced reservations. Serious stargazers will need to book in advance online to enjoy the nighttime tours, which include guided viewings from three tourist-friendly telescopes (two are 12in and one is 14in). Plan a visit around the new moon cycle as the full moon blocks out many constellations. There are a few guest rooms at the complex, so look into staying overnight (dinner and breakfast are included).