Coronagraph

The Koronograf, Eng. Coronagraph, was developed around 1930 by the French astronomer Bernard Lyot and Ferdinand is an astronomical instrument for observing the solar atmosphere, especially the inner corona. It is made telescopic and special devices for damping of the sunlight.

Since the brightness of the solar corona is about a million times less than that of the photosphere, the over radiant sunlight must be hidden. This is done by a cone diaphragm and special filters, creating a kind of artificial solar eclipse occurs.

Coronagraph also be used to observe the surroundings of bright stars to observe, for example, the planet Fomalhaut b in the neighborhood of Fomalhaut, or around the galaxy a quasar as in 3C 273