1. Lockheed Palo Alto Research Laboratory, Palo Alto, CA 94304
2. Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181, Japan
3. Institute of Space and Astronautical Science, Sagamihara, Kanagawa 229, Japan
4. Mullard Space Science Laboratory, University College London, Holmbury, U.K.
5. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822
6. E. O. Hulburt Center for Space Research, U.S. Naval Research Laboratory, Washington, DC 20375
7. National Astronomical Observatory of Japan, Mitaka, Tokyo 181, Japan
8. Rutherford Appleton Laboratory, Didcot, U.K.
9. Department of Physics, Faculty of Science, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
10. Department of Astronomy, Faculty of Science, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan