Solar Eclipse on 29 March 2006

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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). 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 Williams expedition is supported by grants from NSF, NASA, and National Geographic. 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.

Print media: High-res TIFF image.

With a unique view from the first Lagrangian point (L1), outside the disturbing influence of Earth's atmosphere, SOHO's Large Angle Spectrometric Coronagraph (LASCO) produces its own eclipse all the time by simply blocking direct light from the solar disk. Other instruments on board look directly at the Sun, with the same advantage of an uninterrupted view - there are no nights on SOHO, and the Moon never gets in the way.

So, when a total eclipse happens to be observable from Earth, SOHO is one of the primary sources of information about what lies in wait for the eager observers in possibly remote locations. This is also the case this time (on 29 March 2006), when a number of expeditions go to e.g. Turkey, Nigeria, or Libya to catch the magic moment. Although SOHO has its own eclipse, there is still a lot to gain from ground based observations, with sophisticated equipment that can be fine tuned for particular goals.

A number of groups collaborate with SOHO, requesting special observations that will be used for comparisons with the ground based images. Details on SOHO support observations can be found at our here. Instruments involved are the Coronal Diagnostic Spectrometer (CDS), the Extreme ultraviolet Imaging Telescope (EIT), MDI (Michelson Doppler Imager), UVCS (Ultraviolet Coronagraph Spectrometer).

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