Amateur astronomers. Group of amateur astronomers observing an annular solar eclipse. In the foreground (right) one astronomer is using a pinhole camera to observe the Sun without damaging his eyes. An annular solar eclipse occurs when the Moon passes between the Earth and the Sun, but the shadow the Moon casts is not long enough to reach the Earth. This gives the appearance of the sun as a bright ring around the dark disc of the Moon. Photographed in 1984, in Papua New Guinea.