(Large)
This painting is intimately linked with The Geographer: they were recorded together in 1713, and sold together in 1729. These paintings reflect the blossoming of scientific enquiry in seventeenth century Europe. At this time, Newton is making the first reflecting telescopes, Louis XIV is building an observatory in Paris, the satellites of Jupiter are being used for navigation at sea, and Huygens has discovered the sixth satellite of Saturn. The old views, that it would be presumptive for man to probe too closely the sky or the Earth, are being replaced by modern principles of science.

Vermeer was a friend of Antoni van Leeuwenhoek, born in the same year, 1632, and living in the same city, Delft. Van Leeuwenhoek invented the microscope, and discovered the cell structure of biological systems, spermatozoa, and bacteria; he was also skilled in navigation, astronomy, mathematics. Furthermore, he was the trustee of Vermeer's estate, and he may be the subject of these two portraits. The portrait of Van Leeuwenhoek by Jan Verkolje seems to have similar features, and also includes a celestial globe.

The astronomer is dressed in a loose robe, his hair behind one ear, a scholar with his passion; he is looking at a book and an accurately rendered celestial globe, made by Jodocus Hondius in 1600. On the table, on a rich oriental tapestry, is an astrolabe, precursor of the sextant; above the globe is a circular chart with radial lines of obscure significance.

Behind the astronomer is a painting: The Finding of Moses, symbolizing the new discoveries being made in science at the time.