White and/or gray patch, sheet or layered clouds, generally composed of laminae (plates), rounded masses or rolls. They may be partly fibrous or diffuse. When the edge or a thin semitransparent patch of altocumulus passes in front of the sun or moon a corona appears. This colored ring has red on the outside and blue inside and occurs within a few degrees of the sun or moon. The most common mid cloud, more than one layer of Altocumulus often appears at different levels at the same time. Many times Altocumulus will appear with other cloud types.