It is in oil on canvas with dimensions 51 cm × 45 cm (20 in × 18 in). An engraving of an astrolabe invented by Adriaan Metius appears in the book on the table in the painting. Portrayals of scientists were a favourite topic in 17th-century Dutch painting and Vermeer’s oeuvre includes both this astronomer and the slightly later The Geographer. Both are believed to portray the same man, possibly Antonie van Leeuwenhoek.

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