Zahn’s celestial hemispheres after Hevellius

A finely engraved pair of celestial hemispheres depicting the northern and southern skies, derived from the celebrated star atlas Firmamentum Sobiescianum by Johannes Hevelius. The hemispheres illustrate the constellations as elaborate figural forms spread across the heavens, accompanied by zodiacal signs and stellar arrangements. The plates were published in Zahn’s Specula physico-mathematico-historica, an ambitious compendium covering astronomy, mathematics, natural philosophy, and cosmography. Zahn, an Augustinian canon and prolific scientific writer, is best known for his works on optics, including Oculus Artificialis, which described devices related to the camera obscura and early optical projection.