'The Phases of the Moon', c 1860.
© Science Museum / Science & Society Picture Library
One of a set of teaching cards published by James Reynolds & Sons, London, England around 1860. Titled 'The Phases of the Moon', the chart was drawn and engraved by John Emslie. The astronomical diagram shows how the Moon's appearance changes during its 29.5-day orbits around the Earth. When none of the Moon's reflected sunlight reaches the Earth it becomes invisible and known as a New Moon. The Moon's disc then grows (waxes) to a half phase, known as first quarter, and then to Full after a similar period. The lunar disc then starts to shrink (wane) back to half phase, known as last quarter, and then back to the start of the cycle, another New Moon.