  We present the first resolved imaging of the milliarcsecond-scale jets in the
neutron star X-ray binary Circinus X-1, made using the Australian Long Baseline
Array. The angular extent of the resolved jets is ~20 milliarcseconds,
corresponding to a physical scale of ~150 au at the assumed distance of 7.8
kpc. The jet position angle is relatively consistent with previous
arcsecond-scale imaging with the Australia Telescope Compact Array. The radio
emission is symmetric about the peak, and is unresolved along the minor axis,
constraining the opening angle to be less than 20 degrees. We observe evidence
for outward motion of the components between the two halves of the observation.
Constraints on the proper motion of the radio-emitting components suggest that
they are only mildly relativistic, although we cannot definitively rule out the
presence of the unseen, ultra-relativistic (Lorentz factor >15) flow previously
inferred to exist in this system.
