A coronagraph is a telescope that is designed to block light coming from the solar disk, in order to see the extremely faint emission from the region around the sun, called the corona.
Coronagraphs can also observe the innermost corona from the ground, but the outermost corona can be reached only from space because of the scattering of sunlight in Earth's atmosphere.
Coronagraph was invented in 1930 by the French astronomer Bernard Ferdinand Lyot (1897 - 1952).
SOHO instruments include several coronagraphs among its instruments (see UVCS, LASCO).
Image sequence as recorded by the LASCO C2 coronagraph of a 'halo' coronal mass ejection. Material ejected in these pictures reached the Earth four days later.
