A NEW, EVOLVED BIPOLAR PLANETARY-NEBULA

Optical imaging and spectroscopy reveal that the ionised region No.252 in the list of Marsalkowa (1974), whose photograph is presented in th e ''Atlas of Galactic Nebulae'' by Neckel & Vehrenberg (1990), is actu ally a planetary nebula. According to Acker et al. (1992), the object should therefore be named as PN G321.6+02.2. The nebula has the follow ing properties: it is located at 2.0+/-0.5 kpc from the Sun, has a bip olar morphology, a giant size (similar to 4 pc!), low densities, a hot (unobserved) central star (T>130000 K), and extreme He and N overabun dances (He/H=0.147+/-10.029, log(N/O)=0.47(-0.38)(+0.20)). The nebula is likely to be in a very evolved evolutionary stage.