Argentina's first astronomical observatory, founded in 1871, sits on a small hill on the western edge of Sarmiento Park. The original Cooke refractor is still in place, alongside later instruments, and the observatory remains an active research institution attached to the university.
The site is also a museum, with the original Gould-era instruments, photographic plates, and a small display on the history of Argentine astronomy. Public observing nights are held monthly when the weather cooperates.