The Large Angle and Spectrometric Coronagraph (LASCO) instrument is a set of three coronagraphs that image the solar corona from 1.1 to 32 solar radii. LASCO is able to take images of the solar corona by blocking the light coming directly from the Sun with an occulter disk. The position of the actual solar disk is indicated in the images by the white circle. The most prominent feature of the corona are usually the coronal streamers. Occasionally, a coronal mass ejection (CME) can be seen being expelled away from the Sun and crossing the fields of view of both coronagraphs. The shadow crossing from the lower left corner to the center of the image is the support for the occulter disk. LASCO images will provide data to study the coronal heating process, solar wind accelleration and the origins and evolution of CME's.
C2 images show the inner corona up to 5.25 million miles away from the sun.
C3 images have a larger field of view: They encompass 32 diameters of the sun or 30 million miles. It is roughly half of the diameter of Mercury's orbit.