Thanks to the much-heralded International Year of Astronomy, this much we know: Galileo used a telescope to observe the moon in 1609. But the inventor of the revolutionary resolutionary device remains unknown, and its early history is muddied by simultaneous discoveries and competing claims.
In a paper posted to the online repository arXiv.org in August, a pair of researchers from the Astronomical Observatory of Trieste in Italy argues that a partial record of telescopic history resides in the works of Jan Brueghel the Elder. Brueghel, a Flemish painter who lived from 1568 to 1625, came from a family of artists: his father and older brother, both named Pieter Brueghel, were famous painters, and his son Jan Brueghel the Younger also attained some renown for his art.
One of Brueghel's paintings, according to study authors Paolo Molaro and Pierluigi Selvelli, contains the first known depiction of a telescope. In Extensive Landscape with View of the Castle of Mariemont, circa 1608–1611, Archduke Albert VII of Hapsburg holds a spyglass of the kind Galileo famously trained on the moon 400 years ago this fall. (Brueghel was Albert's court painter.) What is more, Molaro and Selvelli argue, letters and documents from the 17th century suggest that the archduke obtained telescopes from their as-yet-unidentified inventor.
Historical records indicate that Albert received early spyglasses from two Dutch telescope pioneers, Zacharias Janssen and Hans Lipperhey, the latter of whom unsuccessfully attempted to patent the device. Either could have been the original inventor of the device, and a 1611 letter from an Italian nobleman to Galileo informs the famous astronomer that the archduke owned telescopes built by the "primo inventore."
In a 1617 Brueghel, The Allegory of Sight, a work made with the painter's sometime collaborator Peter Paul Rubens, a more sophisticated telescope appears on an adjustable mount. Several indicators—the instrument's length, its large eyepiece, and a narrowing of the tube near the eyepiece—hint that it was a Keplerian model, named for Johannes Kepler, the German astronomer and contemporary of Brueghel. Keplerian telescopes used a pair of convex lenses to magnify distant objects, permitting a wider field of view than the early spyglasses of Galileo, Lipperhey and others, which had a concave lens at the eyepiece.
Such a design had been described in principle by Kepler in 1611, Molaro and Selvelli note, but a published description of an actualized Keplerian scope did not appear until 1631. But once again the historical record provides a possible explanation to fill out the hints provided by Brueghel: A German Jesuit priest named Christoph Scheiner wrote in 1631 that he had built a Keplerian telescope as early as 1614 and had shown it to Archduke Maximilian III, the brother of Brueghel's patron, Archduke Albert VII.
Detail of The Allegory of Sight: Wikimedia Commons