  We present HST Faint Object Camera observations of the asteroid 1 Ceres at
near-, mid-, and far-UV wavelengths (lambda = 3636, 2795, and 1621 A,
respectively) obtained on 1995 June 25. The disk of Ceres is well-resolved for
the first time, at a scale of ~50km. We report the detection of a large, ~250km
diameter surface feature for which we propose the name ``Piazzi''; however it
is presently uncertain if this feature is due to a crater, albedo variegation,
or other effect. From limb fits to the images, we obtain semi-major and
semi-minor axes of R_1=484.8+/-5.1km and R_2=466.4+/-5.9km, respectively, for
the illumination-corrected projected ellipsoid. Although albedo features are
seen, they do not allow for a definitive determination of the rotation or pole
positions of Ceres, particularly because of the sparse sampling (two epochs) of
the 9 hour rotation period. From full-disk integrated albedo measurements, we
find that Ceres has a red spectral slope from the mid- to near-UV, and a
significant blue slope shortward of the mid-UV. In spite of the presence of
Piazzi, we detect no significant global differences in the integrated albedo as
a function of rotational phase for the two epochs of data we obtained. From
Minnaert surface fits to the near- and mid-UV images, we find an unusually
large Minnaert parameter of k~0.9, suggesting a more Lambertian than lunar-like
surface.
