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 wondered how scientists know so much about the Sun? 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 Yohkoh Observatory was launched on August 31, 1991, from the island of Kyushu in Japan. Ever since, the satellite has sent back numerous 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 spectacular 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. Specifically, scientists want to know why X-rays and gamma rays are released during this type of event. 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 scientific instruments. This power shutdown was triggered by an annular eclipse of the Sun that occurred over parts of the Pacific Ocean that same day. Efforts are being made to recover the spacecraft. Overall, the Yohkoh spacecraft has been highly successful and has provided real-time monitoring of solar activity for the sake of space weather studies.

Last modified January 9, 2002 by Jennifer Bergman.

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