Atlas of monochromatic images of planetary nebulae
  We present an atlas of more than one hundred original images of planetary
nebulae (PNe). These images were taken in a narrow-band filter centred on the
nebular emission of the [N II] during several observing campaigns using two
moderate-aperture telescopes, at the Complejo Astron\'omico El Leoncito
(CASLEO), and the Estaci\'on Astrof\'isica de Bosque Alegre (EABA), both in
Argentina. The data provided by this atlas represent one of the most extensive
image surveys of PNe in [N II]. We compare the new images with those available
in the literature, and briefly describe all cases in which our [N II] images
reveal new and interesting structures.
