Alimited amount of information is available on one of the first remarkable scientists born in South America: Buenaventura Suárez. Born in the 1670s in Santa Fe, the first port city of Argentina (then part of the viceroyalty of Peru), he studied under the Jesuits at the College of the Immaculate Conception, which was very near his home and is still in operation today. After graduation, he entered the Jesuit seminary and attended the University of Córdoba (in Argentina), also founded by the Jesuits earlier in the 17th century. As a young priest, he was sent to the San Cosme and San Damián mission on the site of the present-day city of Posadas.

Along with a strong drive to help and guide the Guarani Indians, Suárez also had a passion for astronomy. With Guarani assistants, he constructed basic astronomical instruments, including an elementary telescope. From 1706 through 1739, he observed, among other things, eclipses of the Sun and Moon and some of the satellites of Venus and Jupiter. The Jesuits had his astronomical predictions for the period 1740–1841 printed in Spain, in a book titled Lunario de un Siglo (Solar Calendar for a Century). In it, Suárez predicted solar and lunar eclipses and phases of the Moon. The last chapter gives guidelines for continuing the solar calendar up to 1903.

Around 1740, the old mission was abandoned, and the new San Cosme mission was founded across the Paraná River. The ruins of that second mission are very near the town of San Cosme and the city of Encarnación in present-day Paraguay. Suárez continued his astronomical observations there with more sophisticated instruments sent from Europe by the Jesuits. During his career, he exchanged information with scientists from Uppsala, Sweden; Peking, China; St. Petersburg, Russia; and Madrid.

Suárez died on 24 August 1750. Some years later, in 1763, King Charles III of Spain banished the Jesuits from all Spanish domains, and the missions were abandoned. Several decades later, the Spanish historian Félix de Azara found remnants of astronomical instruments while he was performing archaeological studies in the mission ruins. Important studies of Suárez’s life and accomplishments have been done separately by Guillermo Furlong, a Jesuit, and L. Hillar Puxeddú, a lawyer and historian.