This is an X-ray image of the Sun taken with the Soft X-Ray Telescope (SXT) on the orbiting Yohkoh satellite. This is an example of the deep, red images of the Sun you might've seen. This particular image was taken on November 23, 1999.
Click on image for full size
ISAS/Yohkoh team/Lockheed Palo Alto Research Laboratory

Yohkoh Mission

Have you ever seen a deep, red picture of the Sun and wanted to know where it came from? Well, your questions may be answered! For most of this decade, the Yohkoh satellite has supplied us with tons of information about our closest star, the Sun.

The Yohkoh Observatory was launched on August 31, 1991, from Japan. Ever since, the satellite has sent back many X-ray and gamma ray images of the Sun. It uses four special instruments, two of which use spectroscopy. The other two use X-rays. Together, they send back images in light we can't normally see.

The main goal of the project was to increase our understanding of solar flares, which are sudden bursts of energy released by the Sun. However, the observatory also aids in the study of coronal mass ejections and other types of solar activity.

The Yohkoh satellite is controlled from the Institute for Space and Astronautical Sciences in Japan. On December 14, 2001, Yohkoh experienced a power shutdown to the science instruments. This power shutdown was triggered by an eclipse of the Sun that occurred over parts of the Pacific Ocean that same day. Efforts are being made to recover the spacecraft. Yohkoh will be considered a great success even if the spacecraft can't be recovered. Yohkoh was especially well known for providing real-time monitoring of solar activity and new data for space weather studies.

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