  The large-redshift (z=3.8) quasar 1208+1011 has recently been discovered to
be a gravitational lens candidate with a separation of 0.47" between the two
imaged components (A and B). NOT (Nordic Optical Telescope) and HST (Hubble
Space Telescope) studies from 1992 probing primarily the continuum light show
that the amplification of A relative to B is almost achromatic with the
canonical value A:B=4+/-0.1. In this paper we present high-resolution optical
images (FWHM=0.4"-0.5") from 1993 of the quasar. From our narrow-band CCD
frames centred on the redshifted Ly-alpha/Nv line at 5900 A we find that
A:B=3.85+/-0.2. Our broad-band I images uncontaminated by line-emission are
found to be affected by PSF variation over a range of 20\arcsec. However, by
iteratively determining the PSF from the images themselves we show that the
data can be accounted for by two point sources with A:B=3.35+/-0.2. These
results imply that the continuum intensity ratio has decreased during 1992-1993
and that the amplification of the emission-line regions relative to the
continuum emitting regions is different in the two components (under the
gravitational lens hypothesis). The most conservative interpretation of these
results is that 1208+1011 is a gravitationally lensed quasar in which component
B is being microlensed, but the possibility that 1208+1011 is a binary quasar
is not excluded by the present data.
