  The eccentric WR+O binary system WR 140 produces dust for a few months at
intervals of 7.94 yrs coincident with periastron passage. We present the first
resolved images of this dust shell, at binary phases ~0.039 and ~0.055, using
aperture masking techniques on the Keck-I telescope to achieve
diffraction-limited resolution. Proper motions of approximately 1.1
milliarcsecond per day were detected, implying a distance ~1.5 kpc from the
known wind speed. The dust plume observed is not as simple as the ``pinwheel''
nebulae seen around other WR colliding wind binaries, indicating the orbital
plane is highly inclined to our line-of-sight and/or the dust formation is very
clumpy. Follow-up imaging in the mid-infrared and with adaptive optics is
urgently required to track the dust motion further, necessary for unambiguously
determining the orbital geometry which we only partially constrain here. With
full knowledge of the orbital elements, these infrared images can be used to
reconstruct the dust distribution along the colliding wind interface, providing
a unique tool for probing the post-shock physical conditions of violent
astrophysical flows.
