The astrolabe image seen on these pages comes from a photograph in:

Webster, Roderick, and Marjorie Webster. Western Astrolabes. (Historic Scientific Instruments of the Adler Planetarium and Astronomy Museum, vol. 1). Chicago: Adler Planetarium and Astronomy Museum, 1998.

The image is contained on p. 41, and is the face of the astrolabe catalogued as M-26. It dates from circa 1250, and comes from England.

Our thanks goes to the Adler Planetarium and Astronomy Museum for their kind permission to use this image.