SOHO

A merger of a space image from the ESA/NASA SOHO spacecraft and an image taken from Kastellorizo, Greece, by the Williams College Eclipse Expedition

A merger of a space image from the ESA/NASA SOHO spacecraft and an image taken from Kastellorizo, Greece, by the Williams College Eclipse Expedition (from Williamstown, Massachusetts) taken on Mar. 29, 2006. Though SOHO can observe the solar corona on the face of the Sun and can observe the outer part of the solar corona, the "doughnut" between those images is not visible from Earth except during total solar eclipses. The central image from SOHO shows the Sun's disk at temperatures around 60,000 - 80,000 K. The outer image from SOHO shows gas at the millions of degrees typical of the sun's corona. Merging the eclipse image with the space image from SOHO allows astronomers to trace features in the corona from their bases on the Sun's surface up until the gas escapes into interplanetary space; some of this gas winds up hitting our Earth's upper atmosphere. 

Credits: Williams College Eclipse Expedition (Jay Pasachoff, Bryce Babcock, Steven Souza, Jesse Levitt, Megan Bruck,Shelby Kimmel, Paul Hess, Anna Tsykalova, Amy Steele), with support from NSF / NASA / National Geographic.