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Comet Hale-Bopp has shown an extremely elevated level of dust activity during its apparition. We examine the dust activity of the comet, particularly the dust jets which were observed so frequently between discovery and perihelion + 5 months. Other results from observations carried out during the observing campaign have shown that the dust emission

We have obtained new narrowband CCD images, spatially resolved intermediate- and high-dispersion spectroscopic observations of the Ring Nebula (NGC 6720). These data reveal that the bright main nebula is not a real ring, but a closed shell. A prolate ellipsoidal geometry for this shell is inferred from the observed tilts in the [N II] velocity

The continuum and emission lines properties of a sample of 73 blazars is studied, investigating differences and similarities among normal low-polarization quasars (LPQ), radio-loud high polarized quasars (HPQ), and BL Lacertae objects (BLL). We found that at variance with LPQ, most HPQ have power law optical continua (fnu_{prop.to}νalpha^ ) with no

IAUC 6714 available at Central Bureau for Astronomical Telegrams.

AXAF, the Advanced X-ray Astrophysics Facility will be the third satellite in the series of great observatories in the NASA program, after the Hubble Space Telescope and the Gamma Ray Observatory. At launch in fall 1998, AXAF will carry a high resolution mirror, two imaging detectors, and two sets of transmission gratings (Holt 1993). Important