The theoretical study of the evolution of massive stars has considerable relevance to many branches of observational astronomy. As an example, one may mention, first, the direct application of theoretical models in interpreting the observed properties of supergiants, and second, the use of calculations of the nucleosynthesis taking place in these stars, together with observed supergiant mass loss rates and supernova calculations, to estimate the rate and type of nucleosynthetic enrichment of the interstellar medium by supergiants.

In this paper, we will review major new results regarding classical Cepheids, in the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC). Specifically, we discuss recent work regarding multimode Cepheids and describe new observations of a W Vir star (HV 5756) and a Cepheid which are each in eclipsing binary systems. An additional interesting pulsating supergiant in an eclipsing system is also identified. Ephemerides for eclipses for the three systems are provided.

What are the characteristic scale lengths and densities for the dark halos of galaxies, and the typical ratios of dark to luminous mass? For elliptical galaxies, the best estimates come from X-ray data which will be discussed in a later session. For spirals, the best estimates come from rotation curves. I will concentrate on the halo parameters for disk galaxies. At the end, there will be a few comments on stellar dynamical data for ellipticals, and on the unique information available for the dark halo of our Galaxy.

The massive O and B-type stars will be among the first targets of the new generation of long baseline optical interferometers (such as the CHARA Array, a 400-m diameter distributed array of five 1-m telescopes). Many of these objects are binary stars for which joint astrometric and spectroscopic observations will provide masses and distances (e.g., 15 Mon; Gies et al. 1993), but there is also great interest in resolving disks of single stars. Early interferometric observations have already resolved the flattened circumstellar disks around some Be stars (Quirrenbach et al. 1994).

Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS), and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope, but detailed models do not produce powerful explosions. There is new and mounting evidence for an asphericity and, in particular, for axial symmetry in several supernovae which may be hard to reconcile within the spherical picture. This evidence includes the observed high polarization and its variation with time, pulsar kicks, high velocity iron-group and intermediate-mass elements material observed in remnants, direct observations of the debris of SN 1987A, etc. Some of the new evidence is discussed in more detail. To be in agreement with the observations, any successful mechanism must invoke some sort of axial symmetry for the explosion. We consider jet-induced/dominated explosions of core collapse supernovae. Our study is based on detailed 3-d hydrodynamical and radiation transport models. We find that the observations can be explained by low velocity, massive jets which stall well within the SN envelope. Such outflows may be produced by MHD-mechanisms, convective dominated accretion disks on the central object or asymmetric neutrino emissions. Asymmetric density/chemical distributions and, for SN 2002ap, off-center energy depositions have been identified as crucial for the interpretation of the polarization.

Eastern Polynesian astronomy was practiced by navigators and astronomer-priests who were in charge of adjusting the lunar calendar and their annual ritual cycle of activities known as ‘The Work of the Gods’. The festivity known in Polynesia as Matariki, Matali'i or Matari'i was related to the heliacal and acronical rising and setting of the Pleiades. A study of 75 marae on the island of Raivavae, Austral Islands and of 7 marae in the island of Raiatea, Society Islands shows that there are alignments towards important star positions associated with this ritual cycle. Their use as observatories has not been documented and therefore these alignments could have served solely ritual purposes. On Easter Island all information regarding the Matariki festival coincides with the arrival of a Spanish expedition in 1770.

Novae (N) and Dwarf Novae (DN) are considered to belong to the class of the Cataclysmic Variables (CVs). The Novalike stars and recently discovered Polars (the AM Herculis-type stars) seem to have the same nature as CVs and probably are members of this class. It is usually assumed that CVs are close binary systems, each system contains a degenerate dwarf and a nondegenerate second component, their period being usually less than 16h (e.g. see: Robinson 1976). A second star is believed to overfill its Roche lobe and its matter flows onto the degenerated component. Then around the degenerated dwarf there arises an accretion disk. This disk and the hot spot where the interaction between the disk and outflowing stream occurs are the main sources of the blue and ultraviolet continuum and strong H and He emission lines.

We present the most extensive, long-slit, high-resolution coverage of the complex planetary nebula (PN), NGC 7026. Ten spectra were acquired using the Manchester Echelle Spectrometer at San Pedro Martir Observatory in Baja California, Mexico, and each shows exquisite detail, revealing the intricate structure of this object. Incorporating these spectra into the 3-dimensional visualization and kinematic program, Shape, and using HST images of NGC 7026, we have produced a detailed structural and kinematic model of this PN. Knowledge of the 3-D structure of this nebula is relevant to understand the physics behind the extended X-ray emission in this object.

A new Edition of the Asiago Catalogue of QSOs (Barbieri et al. 1982) is available on magnetic tape. It contains essentially all the information of the previous editions updated with the papers published before Dec.31, 1984. The catalog should be essentially complete to that date in respect to objects having slit spectra (2330 objects), while it is seriously incomplete regarding candidates discovered by objective prism or grism/grens surveys after 1982 (279 such objects included in the present version).

Commission 53 met in August 12, 2009. Outgoing President Michel Mayor chaired the meeting, and there were several dozen members present, including incoming President Alan Boss, incoming Vice President Alain Lecavelier des Etangs. Commission 53 (C53) was founded at the 2006 Prague General Assembly of the IAU. After a period of 6 years, C53 will come up for renewal at the 2012 IAU General Assembly in Beijing, China. For the moment, more than 150 IAU members have asked to be members of C53 and few dozen non-IAU members having asked to be informed of the commission activity.

For many generations astronomers have been fascinated by open clusters of stars, of which many are found close to the central plane of the Milky Way. Only in comparatively recent years, however, has it become possible to derive reasonably consistent distances for these stellar systems. The difficulty was that until techniques of photoelectric photometry in at least three colours were developed, there were no reliable estimates of the amount of interstellar absorption and reddening.

HRCAM (High Resolution CAMera) is a Canon 50D 15-megapixel digital SLR camera equipped with a Sigma 4.5 mm f/2.8 fish-eye lens. It was installed at Dome A on the Antarctic plateau in January 2010 and photographs the sky every 15 minutes. Primarily functioning as a site-testing instrument, data obtained from HRCAM provide valuable statistics on cloud cover, sky transparency and the distribution and frequency of auroral activity. We present a first look at data from HRCAM during 2010, including an overview of how we intend to reduce the images. We also demonstrate the potential of stellar photometry by using linear combinations of the in-built Canon RGB filters to convert instrumental magnitudes into the photometric BVR bands.

A series of VLBI surveys of complete samples of radio sources selected at 5 GHz (Pearson & Readhead 1988, hereafter PR; Xu et al. 1995 and references therein) has revealed that ≃ 10% of the objects are “Compact Symmetric Objects” (CSOs), in which high-luminosity radio emission regions are seen on both sides of the center of activity on scales less than one kiloparsec (Phillips & Mutel 1982; Readhead et al. 1984; Conway et al. 1992; Wilkinson et al. 1994). In order to be sure that an object is a CSO, either the center of activity must be pinpointed (Taylor et al. 1996) or compelling morphological evidence of symmetric structure must be found.

This paper examines the distribution of pulsars in the Galaxy and compares it with the distribution of supernova remnants. The dispersion measure has been used as a distance indicator to obtain the distribution in luminosity, z-distance and period of the pulsars. The z-distance distribution is similar within the uncertainties to that of the supernova remnants. An estimate of the total number of pulsars in the Galaxy with a peak luminosity ≥ 1 fu(dm)2 gives 5 × 105 within a factor of 10. The data is consistent with the hypothesis that pulsars are formed at the same rate as supernovae, if the pulsars are assumed to have a timescale of 107yr.

A survey of Kiso UV-excess galaxies (KUGs) has been made using the 105-cm Kiso Schmidt telescope. We selected three galaxies of Ic-type (i.e. irregulars with clumpy HII regions). KUGs 1618+373, 1624+404 and 1626+413, and observed them together with a clumpy irregular galaxy Mrk 297 to clarify their star formation activity (Maehara et al. 1986).

Searching for globular cluster candidates in nearby galaxies such as M31 is the first step to study the characteristics of extragalactic globular cluster systems. Previous searches for M31 globular clusters were mostly based on visual inspection of photograpic plates. We have selected globular cluster candidates from a wide-field Washington CCD survey of M31, using various methods: color-magnitude diagrams, color-color diagrams, point spread function subtraction and visual inspection of the objects. The efficiency and accuracy of these methods for finding globular clusters are presented.

Since it was founded early in the 1980′s, the IAU Meteor Data Center (IAU MDC) has accumulated a large number of the meteoroid orbits measured worldwide so as to make these freely available to all interested researchers. The total number of orbits available is about 68,000, of which about 6,000 were determined using optical techniques (photographic or TV), the bulk having been detected using decameter radars. The observation sites range from various locations in the U.S.A., Canada, Australia, and in the former Soviet Union and Czechoslovakia; radar orbits from the Soviet Equatorial Expedition to Somalia are also archived. About 39,000 of the 62,000 radar orbits are derived from the Harvard Radar Meteor Project. Most of these programs were carried out during the 1960's and 1970′s, but still represent our best knowledge of the orbital distribution of interplanetary particles in the size range from 100 μm to 1 meter. A new survey currently in progress in New Zealand has so far rendered over 350,000 orbits, and it is anticipated that these will soon become available through the IAU MDC. Presently the 68,000 orbits archived in the IAU MDC are only available on magnetic recording media, but it is planned that they will shortly be made accessible via anonymous ftp.

We discuss a model for polarization of pulsar radio emission, based on the assumption that waves propagate in two elliptically polarized natural modes. Some results from numerical simulation of single pulses are discussed with emphasis on circular polarization, microstructures and single pulse statistics.