AN EVENT IN THE LIGHT-CURVE OF 0957-B LIGHT-CURVE(561A AND PREDICTIONOF THE 1996 IMAGE)

CCD photometry of the gravitational lens system 0957+/-561A, B in the g and r bands was obtained on alternate nights, weather permitting, fr om 1994 December through 1995 May using the Double Imaging Spectrograp h (DIS) on the Apache Point Observatory (APO) 3.5 m telescope. The rem ote observing and fast instrument change capabilities of this facility allowed accumulation of light curves sampled frequently and consisten tly. The Honeycutt ensemble photometry algorithm was applied to the da ta set and yielded typical relative photometric errors of approximatel y 0.01 mag. Image A exhibited a sharp drop of about 0.1 mag in late 19 94 December; no other strong features were recorded in either image. T his event displays none of the expected generic features of a microlen sing-induced flux variation and is likely to be intrinsic to the quasa r; if so, it should also be seen in the B image with the lensing diffe rential time delay. We give the expected 1996 image B light curves bas ed on two values of the time delay and brightness ratio which have bee n proposed and debated in the literature. Continued monitoring of the system in the first half of 1996 should easily detect the image B even t and thus resolve the time-delay controversy.