Four planetary nebulae (PNe) with conspicuous point-symmetric morphology are studied in this paper through high-quality imagery and long-slit echelle spectroscopy. Point symmetry is also found in the velocity space, and this is related to particular forms of bipolar collimated outflows. Morphology and kinematics together reveal the presence of

We have acquired [O III] lambda5007, H I lambdalambda6563 and 4861, and [S II] lambdalambda6717 and 6731 imaging of the bipolar outflow source NGC 6445. As a result, we find that density is preferentially enhanced within an interior optical/radio emission annulus and takes a maximum value ~1.1x10^3 cm^-3. Visual extinction appears also to be

We consider here a representative set of delta Scuti stars observed in the Praesepe cluster, thanks to recent efforts of multi-site networks. We show that the effect of rotation on the determination of fundamental parameters {Mbol} and {Teff} cannot be neglected when modelling fast rotators as delta Scuti stars. We propose a method to take this

We report the first reliable measurement of the nebular [O i] lambda 5577 emission line in the Orion nebula. Diagnostic diagrams based on the [O i] lambda lambda 5577, 6300, and [N i] lambda lambda 3467, 5198, 5200 emission lines indicate that the bulk of the nebular emission in the partially ionized zone of the Orion nebula is produced in regions

We present lithium observations of 35 stars previously reported by Wichmann et al. (1996) to be possible new weak T Tauri stars (WTTS) discovered by ROSAT in the Taurus-Auriga star-forming region. These stars were identified on the basis of low-resolution optical spectra. We have used our higher resolution spectra for measuring the equivalent

The eighth STEPHI international multi-site campaign was devoted to the δ Scuti Star V647 Tau of the Pleiades Cluster and was carried out in the period 1997 Nov 19-Dec 13. Analysis using two methods gave the same result. Five pulsation frequencies including both radial and non-radial modes are excited in this star. The dominant frequency p = 20.408c