Figure 1. Evolution of the nightly average <R_c> magnitude from 1994 November to 1995 February. Time is given as days since the start of the first X-ray outburst (5 August 1992 = JD 2448840).
Panel a (top) shows the data for GRO 0422+32 with the possible long-term trend illustrated by a dotted line, while
panel b (bottom) shows the data for a nearby check star (approximately 30" NW of the variable), which illustrates the long-term stability obtained with the 1.2-m CCD camera for this R_c ~ 21 star.