The SOlar and Heliospheric Observatory (SOHO), a coolaboration between ESA and NASA, was launched in December 1995 and is now suspended at the L1 Langrangian pointwhere the gravitational pull of the Earth and Sun are equal and opposite. Theoretically then, SOHO could float there for ever, providing us with a view of the Sun uninterrrupted by atmospheric distortion. In practice however, its planned lifetime was until 1998, but was extended to until 2003.

The LASCO instrument is a set of three coronagraphs that image the solar corona at distances between 1.1 and 32 solar radii from the Sun. The orange C2 coronagraph images the corona out o about 7 solar radii; and the C3 (blue), the wide-angle coronagraph images it out to 32 solar radii.