Christopher W. Mauche Lawrence Livermore National Laboratory, L-41, P.O. Box 808, Livermore, CA
Janet A. Mattei* AAVSO, 25 Birch Street, Cambridge, MA 02138
Preliminary results of a program of simultaneous optical (AAVSO
observers) and extreme ultraviolet photometric (Extreme Ultraviolet Explorer)
observations of dwarf novae in outburst are presented, with emphasis on the
constraints imposed by the observations on the disk instability theory.