  High-resolution mid-infrared images have been obtained in N-band and Q-band
for the proto-planetary nebula IRAS 16594-4656. A bright equatorial torus and a
pair of bipolar lobes can clearly be seen in the infrared images. The torus
appears thinner at the center than at the edges, suggesting that it is viewed
nearly edge-on. The infrared lobes correspond to the brightest lobes of the
reflection nebula seen in the Hubble Space Telescope (HST) optical image, but
with no sign of the point-symmetric structure seen in the visible image. The
lobe structure shows a close correspondence with a molecular hydrogen map
obtained with HST, suggesting that the dust emission in the lobes traces the
distribution of the shocked gas. The shape of the bipolar lobes shows clearly
that the fast outflow is still confined by the remnant circumstellar envelope
of the progenitor asymptotic giant branch (AGB) star. However, the
non-detection of the dust outside of the lobes suggests that the temperature of
the dust in the AGB envelope is too low for it to be detected at 20 microns.
