The data in this archive were obtained by the X-ray detectors on board
the ASCA X-ray satellite observatory.
ASCA (formerly named Astro-D) is Japan's fourth cosmic X-ray astronomy
mission and was successfully launched on February 20,
1993. The first eight months of the ASCA mission were devoted to performance
verification, after which the project changed to a general/guest observer program for the
remainder of the mission. In this phase the observing program is open to
astronomers based at Japanese and US institutions, as well as those who are
located in member states of the European Space Agency.
Description of the ASCA Mission
"The X-ray astronomy satellite ASCA" (Tanaka, Y., Inoue, H. & Holt, S., 1994, PASJ, 46, L37)