Sunspot AR 10810, observed Sept. 23, 2005 with the Dunn Solar Telescope at the NSO. At this scale, the Earth is as big as the dark 'umbral' region. (Courtesy: Friedrich Woeger, KIS, and Chris Berst and Mark Komsa, NSO/AURA/NSF.)
This image appears in the Technology Through Time article: #52 Sunspots from A to B - solar magnetism