The Vatican Observatory is one of the oldest active astronomical observatories in the world, with its roots going back to 1582 and the reform of the Julian calendar. Today there are 15 Jesuits from many different countries on the staff of the Observatory, who study the universe through solid, scientific methods. They stand at the forefront of scientific research covering a broad range of topics, from an examination of the tiniest specs of interplanetary dust to the origins and structure of the universe. The Jesuit astronomers of the Vatican Observatory have contributed to discoveries in many fields from the origins of our solar system to the structure of galaxies. Scientists throughout the world recognize their work in planetary sciences, cosmology and philosophy, and stellar and extragalactic astronomy.
The Observatory has its headquarters in the gardens of the Papal Summer Residence in Castel Gandolfo, Italy, and a research center, the Vatican Observatory Research Group, in Tucson, Arizona, one of the most important centers in the world for observational astronomy. Most of the observational research today takes place at the Observatory's telescope on Mt. Graham in Arizona. Besides several older telescopes the headquarters outside Rome house a library with a number of historically important scientific works, a collection of antique astronomical instruments, one of the most important meteorite collections in the world and a recently renovated state of the art meteorite laboratory.