History books generally identify the inventor of the telescope as one Hans Lippershey, an eyeglass maker in the Netherlands in the late 16th century. The story goes that Lippershey saw a couple of children playing with lenses in his shop, and overheard them exclaim that looking through the lenses made a nearby building seem larger.
Lippershey experimented a bit further, and built a device he called a "looker," using a convex objective lens and a concave eyepiece. Galileo snagged an early version of the telescope as it spread through Western Europe, and improved the design to make the first observations of the moons of Jupiter, among other momentous findings.
But Johannes Kepler suggested the instrument could be improved even more in 1611 by using a convex eyepiece, resulting in a wider field of view. Nor was it necessary any longer to plate the eyepiece so close to the eye of the observer. The only disadvantage: the resulting image is inverted. Astronomers adapted accordingly. The first Keplerian telescopes were believed to appear around 1631.
Of course, there is evidence that Lippershey may not have been the first to build a telescope after all. His 1608 patent application was denied because the knowledge that combinations of lenses could magnify objects was already well known by that time. And now Kepler's own contribution to the development of the telescope is coming into question, according to astrophysicists at the Instituto Nazionale di Astrofisica in Trieste. The evidence can be found in a painting by a Flemish artist named Jan Brueghel the Elder, which depicts a telescope of Keplerian design even though the canvas was painted a good 15 years before its supposed invention.
Paolo Molaro and Pierluigi Selvelli have studied five paintings by Brueghel depicting telescopes, and maintain the artist made the first such representation of the telescope in his work, "Extensive Landscape with View of the Castle of Mariemont." Brueghel was court painter to Archduke Albert VII of Habsburg, and it just so happens that Lippershey gave one of his earliest telescopes to Albert. Molaro and Selvelli believe the telescope in the painting is, in fact, that particular instrument.
Another painting, "The Allegory of Sight," depicts a telescope that seems very much to be of Keplerian design — except the canvas dates from 1617, well before the first Keplerian telescopes supposedly were built. Molaro and Selvelli base their conclusion on the length of the painted instrument — is is longer than the earlier Galilean designs, just like Kepler's telescopes — and the size of the eyepiece, designed to limit how close the eye can be brought to the eyepiece lens.
It's always a bit risky to draw scientific conclusions from works of art: all artists take liberties with their subjects when creating a painting, after all. But sometimes historical paintings can offer tantalizing clues, particularly when so little is known about an era. I guess we'll have to wait and see if art (or science) historians manage to dig up some corroborating evidence to support Molaro and Selvelli's hypothesis. In the meantime, it certainly makes for an intriguing premise.