The young astronomer holds a celestial globe with constellations shown in the form of animals. Among those visible are some of the northern and zodiacal constellations: at the top, Draco; on the left, Ursa Major and, below it, Leo; on the right, beneath the encircling brass ring, Bubuleus. The stand for the globe is on the right, and a quadrant is in the foreground. The attribution and dating depend on the similarity of this picture with a painting of an astronomer, dated 1685 and signed by van Deuren (New York, Christophe Janet, 1978). The model and globe appear to be the same in both works.