THE MIDINFRARED STRUCTURE OF THE BIPOLAR NEBULAE AFGL-915, AFGL-618, AND AFGL-2688

We have obtained near diffraction-limited images of three bipolar PPN at UKIRT in October, 1993: AFGL 915 (the ''Red Rectangle''), AFGL 618, and AFGL 2688 (the ''Egg Nebula''). Images were taken at unidentified infrared (UIR) emission feature wavelengths and at several continuum wavelengths in the 10 and 20 mu m atmospheric windows. In all three PP N the emission is dominated by a central point source with fainter emi ssion extending for several arcsec. In AFGL 2688, the mid-IR emission is extended in the same direction as the main optical lobes. In AFGL 9 15, the UIR feature emission is spatially separated from the central s ource. The ''spikes'' that have been observed at 2 mu m and give the n ebula its rectangular appearance are also visible at 10 mu m.