The Sun - April 10, 2013

The Sun - April 10, 2013

These images of the Sun were taken at the Public Observatory on April 10, 2013 at noon, while visitors used safe solar telescopes to observe features on our closest star.

The image on the left shows the surface, or photosphere, of the Sun.  Glowing at 5,600°C (10,000°F), the photosphere sports a number of dark sunspots.  These are regions of intense magnetic activity where the gas trapped on the surface is about 1000° cooler, and thus darker.  The large sunspot toward the lower right is several times the size of the Earth.

The image on the right shows the atmosphere, or chromosphere, of the Sun.  This gas is less dense but hotter, at 20,000°C (35,000°F). It can be seen by looking at the Sun with filters that allow through just one color of red light.  Features of the chromosphere include arches of gas called prominences that extend off the edge of the Sun.  The dramatic prominence to the lower left stands at least five times as tall as the Earth.

Sunspots are often the source of solar flares – explosions of energy caused by the collision or snapping of magnetic arches above the Sun.  A moderate solar flare happened 15 hours after this picture was taken, in the sunspot to the upper left. The sunspot is named AR 1719. Visitors at the Observatory the next day studied the bright yellow clouds of gas around the sunspots.  These clouds, called plages, can glow brightly for minutes or hours after a solar flare occurs.

Telescope: Lunt 100mm Hydrogen-alpha

Camera: Lumenera SKYnyx 2-2M

  • WEB12825-2013

  • Copyright/Owner: Smithsonian Institution
  • Source: Smithsonian Public Observatory Project
  • Photographer: Geneviève de Messières
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