Sunspot with exceptional detail

Two white light images of a sunspot, using different exposures, and obtained during exceptionally good seeing conditions at Kitt Peak. One view is the more conventional picture of a unipolar sunspot near the solar disk center, taken from a full-disk magnetogram with an exposure of 1/500 seconds. Suspended over the umbra is a rope-like light bridge. The outer diameter of the spot is about 32 arc seconds (14 thousand miles). The other view is the same but overprinted with umbral information obtained from a longer exposure of 1/150 seconds. This shows fibrous intrusions delineating still darker areas. The shorter exposure reveals the solar granulation and the longer brings out details in the darker umbrae. When these two exposures were suitably combined. the umbra of one small sunspot was resolved into an approximately filamentary structure, connecting to the penumbra, along with a number of featureless voids. Taken on September 9th 1990 by Dr Bill Livingston with the McMath-Pierce Solar Telescope.