This image shows an active region of the Sun. The National Solar Observatory, Sacramento Park, CA, made it using one of several types of telescopes. Information about the Sun’s activity is used to support of space weather forecasts. NSO has equipment that acquires solar images in the hydrogen-alpha line (once per minute), in continuum (once every ten minutes), and in line-of-sight magnetic fields. Images are passed through an automatic image-processing pipeline and are subsequently analyzed and displayed using various software tools. The areas marked, "plage" represent an area of brightnes. Filiments are gas clouds above the Sun's surface.
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Image courtesy of the National Solar Observatory at Sacramento Peak

The Chromosphere

Above the photosphere is the chromosphere, a region about 2500 kilometers thick. Just prior to and just after the peak of a total solar eclipse , the chromosphere appears as a thin reddish ring. The conspicuous color of the chromosphere (compared to the mostly white corona) led to its name (meaning ``color sphere.'') The chromosphere is most easily viewed in emission lines such as Hydrogen alpha, where bright regions known as plages, and dark features called filaments are visible. Filaments are the name given to prominences when they are seen on the solar disk.

Spicules are visible in the chromosphere on the limb (the edges) of the sun. They are jets of plasma shooting up from supergranule boundaries. While small compared to the sun, these plasma jets are actually the size of earth!

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