We have acquired narrowband imaging of NGC 3587 (the Owl Nebula) in the transitions [O II] λλ3727, 3729, H I λ4861, [O III] λ5007, H I λ6563, [N II] λ6584, [S II] λ6717, and [S II] λ6731. As a result, we are able to evaluate the variation of excitation and electron density over the projected envelope of the source. We propose that the Owl Nebula

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As a parallel result from a project aimed at determining accurate distances to more than 30 Planetary Nebulae using the extinction-distance method, we report here the serendipitous discovery of a giant halo around NGC 7027. We obtained the spectra of more than 50 field stars around each PN with the LDSS2 multi-slit spectrograph in the 4.2m

We present four lines of evidence leading to the conclusion that the HII regions in the discs of normal galaxies,notably the highly luminous regions,are density bounded: (1)The relation of central Hα surface brightness to total luminosity of a region departs from the predictions of uniformly ionization bounded systems (2)The geometry and intensity

A description of the emergence of large concentrations of magnetic fields (active regions) at the solar surface is presented. The dark structures known as SUNSPOTS are a consequence of this process....

We present the chemical analysis of a new set of stars known to harbor low mass companions, namely HD 1237, HD 52265, HD 82943, HD 83443, HD 169830, and HD 202206. In addition, we have also analyzed HD 13445 and HD 75289, already studied elsewhere. The abundances of C and alpha -elements O, S, Si, Ca and Ti are presented and discussed in the