Sunspots are relatively cool spots on the surface of the sun, caused by intense localized variations in the sun’s magnetic field. They are actually quite bright, however sunspots appear dark in contrast to the more luminous surrounding material. Individual spots can last from a few hours to a few months. Most solar flares and coronal mass ejections occur around sunspots. The number of sunspots rises and falls following the eleven year solar cycle.
The prominent sunspot group at the upper left is designated AR 1339. Its largest spot extends about three times the diameter of the earth.
Solar disk on November 6, 2011 from Carlisle, Massachusetts
Nikon D300s at prime focus of Questar 3.5″ with solar filter, 1400mm, f/16, 1/8000 s, ISO 200