This painting by the dutch painter Gerrit Dou, named Astronomer by Candlelight depicts an astronomer measure the distance between two points on a celestial globe, working late through the night, a time which encourages the use of strong contrast and differences in tonal ranges between the lights and the darks. Dou cleverly used practical lighting from the candle on the table as the sole source of illumination. We also observe a strong fall off into immediate shadow, a very realistic lighting approach as such a small source would create harsher shadowing and more intense fall off. Larger sources consequently create softer shadows. In addition, we must also appreciate the meticulous details within Dou's artwork, where we observe every single element within the book, the globe and more precisely the hourglass.