Yohkoh (, Sunbeam in Japanese), known before launch as Solar-A, was a Solar observatory spacecraft of the Institute of Space and Astronautical Science (Japan), in collaboration with space agencies in the United States and the United Kingdom. It was launched into Earth orbit on August 30, 1991 by the M-3SII rocket from Kagoshima Space Center. It took its first soft X-ray image on September 13, 1991, 21:53:40, and movie representations of the X-ray corona over 1991-2001 are available at the Yohkoh Legacy site. Description The satellite was three-axis stabilized and in a near-circular orbit. It carried four instruments: a Soft X-ray Telescope (SXT), a Hard X-ray Telescope (HXT), a Bragg Crystal Spectrometer (BCS), and a Wide Band Spectrometer (WBS). About 50 MB were generated each day and stored on board by a 10.5 MB bubble memory recorder. Because SXT utilized a charge-coupled device (CCD) as its readout device, perhaps being the first X-ray astronomical telescope to do so, its "data cube" of images was both extensive and convenient, and it revealed much interesting detail about the behavior of the solar corona. Previous solar soft X-ray observations, such as those of Skylab, had been restricted to film as a readout device. Yohkoh therefore returned many novel scientific results, especially regarding solar flares and other forms of magnetic activity. The mission ended after more than ten years of successful observation when it went into its "safehold" mode during an annular eclipse on December 14, 2001, 20:58:33 and the spacecraft lost lock on the sun. Operational mistakes and other flaws combined in such a way that its solar panels could no longer charge the batteries, which drained irreversibly; several other solar eclipses had successfully been observed. On September 12, 2005, the spacecraft burned up during reentry over South Asia. The time of reentry, as provided by the U.S. Space Surveillance Network, was 6:16 pm Japan Standard Time (JST). Instruments Yohkoh carried four instruments : The Soft X-ray Telescope (SXT) was an X-ray telescope with glancing incidence X-ray mirror and a CCD sensor. There was also a co-aligned optical telescope using the same CCD, but after the failure of the entrance filter in November 1992 it became unusable. The CCD was 1024×1024 pixels with pixel angular size of 2.45″×2.45″, a point-spread function (core width FWHM) of about 1.5 pixels (i.e. 3.7″), a field of view of 42′×42′, which was a little larger than the