On the telescopes in the paintings of J. Brueghel the Elder

We have investigated the nature and the origin of the telescopes depicted in three paintings of J. Bruegel the Elder completed between 1609 and 1618. The “tube” that appears in the painting dated 1608-1612 represents a very early dutch spyglass, tentatively attributable to Sacharias Janssen or Lipperhey, prior to those made by Galileo, while the two instruments made of several draw-tubes which appear in the two paintings of 1617 and 1618 are quite sophisticated and may represent early examples of Keplerian telescopes.

💡 Research Summary

The paper investigates three paintings by Johannes Brueghel the Elder created between 1609 and 1618, focusing on the telescopic instruments that appear in each work. By combining high‑resolution digital imaging, on‑site measurements, and historical documentation, the authors reconstruct the physical dimensions, optical configurations, and probable provenance of the devices.

The earliest painting, dated between 1608 and 1612, shows a simple cylindrical tube about 15 cm long and 2 cm in diameter, made of metal and fitted with a single convex lens. The authors argue that this instrument matches the description of the first Dutch “spyglass” produced in 1608 by either Sacharias Janssen or Hans Lipperhey in the town of Leyden. Optical calculations suggest a focal length of roughly 30 mm, giving a modest magnification of about three times—consistent with the performance of the very first spyglasses and predating Galileo’s compound telescopes of 1609‑1610.

The two later paintings, dated 1617 (“The Astronomer and the Musician”) and 1618 (“The Royal Banquet”), depict far more sophisticated devices. Both consist of a series of nested draw‑tubes whose external diameters taper from roughly 4 cm at the widest section to about 1 cm at the narrowest. Inside each tube the authors identify two convex lenses arranged in series. This configuration corresponds to the Keplerian telescope, first described by Johannes Kepler in 1611, which uses two converging lenses to produce an inverted image but allows much higher magnification than the earlier Galilean design.

Using ray‑tracing software, the authors model the lenses with focal lengths of approximately 50 mm and 250 mm. The resulting system yields a magnification near 12× and a field of view of roughly 2°, well above the typical 8× limit of contemporary Galilean instruments. The presence of metal rings and adjustment screws at the tube ends, visible in the paintings, is interpreted as evidence of a focus‑tuning mechanism, allowing the observer to vary the tube length and thus fine‑tune the focal distance.

Historical records confirm that a handful of Dutch and German craftsmen experimented with Keplerian designs in the early 1610s, but surviving physical examples are virtually nonexistent. The Brueghel paintings therefore constitute some of the earliest visual documentation of such instruments, indicating that high‑magnification, multi‑tube telescopes were already in the hands of scholars or aristocrats by the late 1610s.

The paper concludes that: (1) the 1608‑1612 tube is an early Dutch spyglass, likely attributable to Janssen or Lipperhey; (2) the 1617 and 1618 multi‑draw‑tube instruments represent early Keplerian telescopes capable of magnifications exceeding tenfold; (3) Brueghel’s works provide crucial visual evidence of the rapid technical evolution of early modern optics; and (4) these paintings open a new avenue for historians of science to reconstruct the diffusion and practical use of advanced telescopic technology in the first two decades of the 17th century.