Narrow-band Imaging of NGC 7026

NGC 7026 is one of the most remarkable bipolar planetary nebulae in the northern sky. There is an increasing interest in sources of this kind, as they indicate that anisotropic outflow phenomena play a significant role in the final evolutionary stages of massive stars. To investigate the spatial distribution of the excitation conditions in this nebula, and to get information about the structure of the progenitor’s red giant wind, we started a multiwawelength survey taking high spatial resolution line images in the visible, near and midinfrared range using the Calar Alto and UKIRT telescopes. The instruments used are the STScI optical coronograph (Paresce & Burrows, ESO Messanger 47, 1987), the MAGIC IR camera (Herbst et al., SPIE Proc.N. 1946, p.605, 1993), and the new MPIA thermal IR imager MAX. We present here some preliminary results, which allows us to estimate the main physical parameters of the central star, to find evidence for significant shock emission at the polar regions of the nebula, and to reveal an unexpected deficit of H2 emission.