A 19th century moving-disc guide to the night skies

A simple device for demonstrating which stars are visible at a particular time of night. The overlay can be rotated to select the date and time, with an oval window over a celestial map revealing the appropriate stars. The firm published similar discs for use all over the world, including the Southern Hemisphere, continuing to issue them into the late 20th century. Although undated, we have estimated the date of this example from the address '32 Fleet Street' on the reverse, used by the Philips' between 1856-79, making this an early example. Later versions were made in Germany.