HaTr 10, a planetary nebula with extremely strong nitrogen lines

Optical spectra and direct images reveal that a very faint, scarcely studie d object (HaTr 10) which appears as an incomplete elliptical ring of 0'.4 x 0'.2 is a heavily obscured planetary nebula with exceptionally strong nitr ogen lines ([N II] gimel 6583/H alpha approximate to 6). In the H alpha/[N II] versus H alpha/[S II] nl diagnostic diagram, the object does not resemb le H II regions or supernova remnants. It is quite far from the locus of th e bulk of(bipolar) planetary nebulae. Photoionization models can well repro duce the observed emission lines, by using a gas of density 500 cm(-3) and with abundances of N = 8.6, O = 8.2, and all other elements with solar abun dances. On our deepest CCD frames the nebula is considerably larger (1'.5 x 1'.0), showing butterfly-like faint extensions. These symmetrical lobes, t he ring around its waist, and the very high nitrogen abundance support the classification of HaTr 10 as an extreme bipolar planetary nebula. We sugges t that very deep frames of nebulae that appear morphologically akin to HaTr 10 should be obtained to enable or support a reliable classification.