John Evershed
India, 2008

This esoteric stamp commemorates the centenary of the discovery that there is an outward flow of gas in sunspots, which are cooler, darker patches on the Sun’s surface. The discovery was made in 1909 by John Evershed (1864–1956), an English astronomer who worked at Kodaikanal Observatory in the mountains of southern India. The radial outflow he discovered is now known as the Evershed effect and was a major contribution to the understanding of the structure of sunspots.

Evershed joined the observatory in 1907 as assistant director and became director in 1911. The design of this commemorative stamp includes Evershed’s sketch showing the tilting of spectral lines across a sunspot caused by the outward motion of gas. This sketch is overlain on a black and white picture of a sunspot.

Although Evershed himself does not appear on the stamp, there is a picture of him, along with Kodaikanal Obervatory, on the first day cover (below).

Stanley Gibbons no. 2542