Nova Muscae 1991 (GRS 1121-684) was discovered by the Watch all-sky x-ray monitor in January 1991, shortly after the start of the outburst. The observations reported here cover part of the initial rise to maximum light in the 6-100 keV range, and the first two weeks of decline. During this period a secondary outburst was seen.
Dri. Dansk Rumforskningsinstitut: Lyngby, May 14-16 1991, 1991, p. 1-10