The Sloane astrolabe (circa 1300) was a scientific tool used in the medieval period to measure the locations of celestial bodies, identify stars and other bodies, and even tell time. (Courtesy of the Trustees of the British Museum)

Ever heard of an armillary sphere, a radio latino or a theodolite?

All were crucial instruments in earlier days of scientific inquiry — a model of a celestial sphere and two sophisticated measurement tools. Painstakingly built by inventors and craftsmen, these and other instruments opened up a world of discovery to curious scientists of medieval and Renaissance Europe. And they’re on full display at Epact.

The website is an electronic compendium of bygone scientific innovation. Its catalogue features 520 instruments by European makers whose creations furthered mathematics and science. Each instrument is accompanied by a description and details about its inventor, purpose and creation. Also available are extensive academic reports about how the instruments were used and what they contributed.

Epact — a play on a medieval word for the age of the moon on the first of the year — is the result of a pact of sorts between four European institutions: the Museum of the History of Science in Oxford; the Museo Galileo in Florence; the British Museum in London; and the Museum Boerhaave in Leiden, Netherlands.

The objects were once advanced technology, such as the Sloane astrolabe (circa 1300). Beneath its complex scrolls is an intricately engraved tool used to measure the locations of celestial bodies, identify stars and other bodies, and even tell time. It was part of the first founding collections of the British Museum.

Epact may make you appreciate the artistry and intricacy of now-obsolete scientific tools or leave you starry-eyed over each instruments’ function and a role.

Either way, a visit to Epact is a glimpse into a bygone world — one in which scientists dared to dream and discover.