  We report on an observing campaign in March 2001 to monitor the brightness of
the later arriving Q0957+561 B image in order to compare with the previously
published brightness observations of the (first arriving) A image. The 12
participating observatories provided 3543 image frames which we have analyzed
for brightness fluctuations. From our classical methods for time delay
determination, we find a 417.09 +/- 0.07 day time delay which should be free of
effects due to incomplete sampling. During the campaign period, the quasar
brightness was relatively constant and only small fluctuations were found; we
compare the structure function for the new data with structure function
estimates for the 1995--6 epoch, and show that the structure function is
statistically non-stationary. We also examine the data for any evidence of
correlated fluctuations at zero lag. We discuss the limits to our ability to
measure the cosmological time delay if the quasar's emitting surface is time
resolved, as seems likely.
