Most pre-college teachers in the United States have not been trained in astronomy. In Texas, astronomical concepts enter the pre-college science curriculum at all levels.

During the last six years, I have presented two different types of workshops: intensive three-week summer institutes for rather small numbers of teachers, and shorter 6- to 18-hour workshops for larger groups.

The University of Texas Astronomy Department and McDonald Observatory have hosted five of the intensive institutes. The institutes were established to offer an opportunity to learn astronomy through hands-on activities (Texas education regulations mandate that 40 per cent of all pre-college science classes should be laboratory oriented), and to introduce the teachers to modern astronomical research and facilities.

Stellar brightness measurements in the far ultraviolet at wavelengths above Lyman α have been obtained from several experiments beginning in 1960. The 1960 data were obtained using mirror telescopes and gas gain ion chambers. They indicated far ultraviolet stellar brightness about 1 magnitude lower than predicted by theory. Subsequent Geiger counter data appear to support this conclusion. The reliability of rocket far ultraviolet stellar photometry, however, is still insufficient, to place great confidence in the above conclusions.

Stellar brightness measurements in the band 1150–1180 Å indicate that there may be a considerably greater deficiency in far ultraviolet stellar emission at wavelengths below Lyman α than above.

The illness which prevented Dr. N. Richter from presiding over Commission 15 sessions in Montreal proved fatal on November 26, 1980.

Books published since 1978 dealing with the subject matter of Commission 15 are: (1) Comets and The Origin of Life, ed. C. Ponnomperuma, 1981, D. Reidel pub. Co., Dordrecht, Holland (designated C. P. Colloq. in Report); (2) Comets, ed. L. Wilkening, Univ. Arizona Press, 1982 (designated Comets, 1982 in Report) contains invited reviews of Tucson, IAU Colloquium No 61, “Comets” Gases, Ices, Grains, Plasma”. Contributed papers will appear in a volume of Icarus. Papers dealing with cometary and asteroidal orbits appear in IAU Symp. 81, 1979 and with cometary grains and meteorites in IAU Symp. 90, 1981. Proceedings of Workshops are: (1) “Experimental Approaches to Comets”, ed. J. Oro, 1978, Lunar and planetary Institute, Pub. 361; (2) “Modern Observational Techniques for Comets”, eds. J. Brandt et al., 1981, JPL Pub. 81-68, NASA.

The current status of observations of energetic particles in the “local bubble” is reviewed. This includes primarily “direct” measurements of cosmic rays made in the Solar System, but also the “remote sensing” made possible by observing cosmic ray produced γ-rays in the nearby interstellar clouds. Since the energetic events responsible for the formation of our local bubble may also have produced copious amounts of cosmic rays, fossil records are examined to determine whether there is a corresponding signature. The observations show that: 1) the cosmic ray (proton) intensity is fairly homogeneous throughout the local bubble and its adjacent interstellar clouds, 2) there is some evidence for a “recent” local cosmic ray injection about 40,000 years ago, 3) on longer time scales (a few million years) the cosmic ray intensity was constant within a factor two, 4) there is apparently some “activity” in the Orion cloud, as evidenced by low energy γ-ray signatures, and 5) there are two unexplained observations – the variations in the energy spectra, in particular the significantly flatter spectrum of heavy cosmic rays (Fe) and the matter path length variation, which yields consistently larger path lengths for the lighter elements (H, He). It is suggested that these observations are compatible with two cosmic ray populations – an older one in equilibrium with losses from the galaxy and a younger one which is not yet strongly affected by losses. The latter could be a cosmic ray signature of the formation of the local bubble.

We briefly review the question of the origin, during a sunspot cycle, of well isolated sunspots. This includes big sunspots like the one observed in Nov. 2006. An overall axi-symmetric morphology is not perfectly observed when the morphological details of both the umbra and of the penumbra are considered. This is especially the case of umbral dots always present inside the core of a sunspot and also of penumbral filaments with non radial parts. However, the distribution of the surrounding fields, including deep layers, the occurrence of persistent coherent running penumbral waves, the magnetic moat behavior, the bright ring phenomena, etc. seem to justify a revival of the naive former but revised (converging motions are considered) Larmor model of a sunspot (as suggested by Lorrain et al. 2006). To discuss the “emergence” of single isolated sunspots from deep layers we performed a quasi-statistical analysis limited to cycle 23. It is based on MDI data taken in the continuum, using the accompanying magnetograms to check our assertion. Surprisingly, single sunspots are definitely and preferably found to occur at low latitude and during the descending branch of the cycle. To explain our observations we speculate about the behavior of the deeply seated magnetic loop, following the original idea of H. Alfven (with whirl rings which follow the global dipolar field when approaching the surface). It could lead to a closed loop approximately orthogonal to the local radius, similar to “smoke rings” arriving at the surface of the Sun and sometimes also called a plasmoid. The ring will only very weakly feel the destabilizing Coriolis force, when emerging at very low latitudes, which seems consistent with our observations.

Mercury transits are important for the investigation of long-term variations in the Earth rotation. They have been observed for more than 300 years. The basic array of this set is the visual observation of contacts (as a rule the second and third ones). The detection of the instant corresponding to the geometrical contact of the solar and Mercury limbs is a difficult task, since during 10s to 60s, the set of phases is observed transforming continuously from one to another. One of the encumbering factors, is the so-called “black drop” phenomenon, i.e., the dark cross-bar formed between the limbs (Struve, 1882; Kuhl, 1929; Wittman, 1974; Morrison et al., 1975). The influence of this factor could be negleted if the observations were distributed uniformly with regard to contacts, observers and observational conditions. In fact, it is far from that and the necessity of reduction corrections arises.

As early as 1968, increases in the complexity of photoelectric observing programs and the variety of sophisticated photometric instruments in use at the Cerro Tololo Inter-American Observatory necessitated the acquisition of a digital data-recording and instrumentation-control system. The diversity of projects to be done with such a system and the obvious need of provisions for extensive future modification and expansion made apparatus oriented around hard-wired logic clumsy and uneconomical. Clearly, the heart of the system was to be a digital computer.

Ionization models for NGC 6210, 7009, 3242 and II 2003 have been constructed from optical and IUE spectroscopic data. The CIV 155 nm resonance line is predicted about ten times stronger than observed. Radiative transfer calculations of the CIV lines in a spherical nebula, assuming partial frequency redistribution, were made to investigate the effects of dust absorption and an additional depopulation of the upper level.

The coronal X-ray emission has been studied in a series of sunpointed Skylark-rocket flights over the period August 1964 to August 1967. Two types of instrument have been used, namely, an array of pinhole cameras, to study the distribution of X-ray sources across the solar disk, and a set of Bragg crystal spectrometers, to examine the detailed spectrum of the emission.

Six rocket flights in all (Skylarks 301, 302, 303, 306, 307, and 406) have provided solar X-ray photographs, covering the wave-band 12–60 Å. The main conclusions of this work may be summarised as follows:

1. (1) Of over twenty separate calcium-plages areas, all those having an area-intensity product greater than 300 were associated with enhanced coronal X-radiation, this ‘threshold’ being merely a function of X-ray camera sensitivity.

2. (2) The plages studied were of from 1st to 4th rotation, indicating the enduring nature of the local coronal X-ray enhancement.

3. (3) Crude spectral analysis, derived from different filters used in a given camera array, showed an increasing contrast between the active region and disk emissions below 25 Å, indicating the probability of the active region coronal material being rather hotter.

4. (4) Photographs of regions on the disk and on the limb showed a typical coronal active region to produce more than 50% of its total X-ray flux from a region within 1 arc minute cube. Electron densities up to 10 times the normal coronal values are required by the measured X-ray brightness of the larger regions.

5. (5) The major part of the emission above 20 Å arises from the (cooler) background corona. Examination of this coronal disk emission revealed strong limb brightening, polar darkening (particularly in the 1964–65 photographs) and a band of slightly enhanced X-radiation near latitude 35 °N. The latter observation was noted on successive flights, in October 1965 and February 1966, and clearly followed the tilt in aspect angle of the solar disk.

Skylarks 304 and 305 were equipped with uncollimated Bragg crystal spectrometers. The former payload, flown in May 1966, revealed strong line emission down to the scan limit at 11 Å. Emission lines of O VII and VIII, Ne IX and X, Fe XVII and XVIII and NI XIX have been identified. All but the O VII series were found to have dominant components arising from a large active region on the solar disk, and an analysis has shown that the complete active-region spectrum is consistent with an electron temperature of 3 million degrees. Intercomparison of the different emission lines indicated coronal abundances of iron, nickel and neon comparable to those derived earlier by Pottasch from an analysis of the solar UV spectrum.

Provisional analysis of the latest flight (Skylark 305 in August 1967), employing crystals of beryl and EDDT in addition to the KAP flown on Skylark 304, has shown strong emission lines of the helium-like ions Mg XI and Si XIII, with weaker but significant intensity in Lyman-α of Mg XII (8·4 Å) and Si XIV (6·2 Å), the latter emission requiring the presence of active region material at a temperature of near 107°K.

Activity of late type stars is enhanced by fast rotation, which is maintained in nearly synchronized close binary systems. Magnetic activity originates in the deep convection zones of stars from where magnetic flux tubes emerge to their surfaces. The gravitational forces in binaries help the clustering of activity features giving rise to active longitudes. These preferred longitudes are observed in binaries from dwarfs to giants. Differential rotation is found in many active stars that are components of binary systems. If these binaries are circularized and nearly synchronized, then there will be a corotation latitude in their surfaces, and its position can be determined by observations and by theoretical calculations. Enhanced activity in binaries could have a reverse effect as well: strong magnetism in a binary component can modify the orbital period by the cyclic exchange of kinetic and magnetic energy in its convective envelope.

We present new observations in the radio continuum of 31 planetary nebulae at 5 and 8 GHz with the Australian Telescope Compact Array. The observations are used to invesigate properties of the interstellar extinction toward Galactic Bulge.

The Galactic neutron star X-ray binary Her X-1 shows a 35-day photometric modulation. Detected across a broad energy range, the modulation is prevalent in X-rays, cycling between low and high states. Since the discovery of the 35-day cycle of Her X-1, the X-ray source has entered and returned from an extended anomalous low state on at least seven occasions. Employing Rossi X-ray Timing Explorer All-Sky Monitor observations, prior predictions that Her X-1 would return from the 2003 - 2004 anomalous low state with a new precession period and accretion luminosity are verified. However, the precession has not been as coherent over recent years as predicted. Potentially there have been more minor anomalous low states between 2004 and the present day.

The processes in interstellar space, as well as the structure of nebulae – including the numerous small condensations around newly formed stars – suggest a relationship to the formation of the cometary cloud surrounding the Sun. Study of carbonaceous chondrites has revealed that in the earliest stage of the solar system's existence frequent periods of brief heating occurred, leading to the formation of very complex organic compounds and also of chondrules of crystalline structure. This was most probably a consequence of cometary collisions. The Tunguska phenomenon illustrates some consequences of a similar collision.

The similarity rules to compare atmospheres with anisotropic and isotropic scattering are reviewed. Omission of a narrow diffraction peak in the scattering pattern is permitted and corresponds to a special application of the similarity rules. It is shown that the extrapolation length for conservative scattering can be found with great precision from a formula involving only ω2 and ω3. An asymptotic expression for high-order scattering in a semi-infinite atmosphere is given and it is shown by some examples that this expression can be used to find by interpolation the terms of any order. Finally, the way in which the contrast between a dark and bright area near the center of the disk of Mars is affected by an overlying haze is computed for isotropic and for anisotropic scattering.

The paper emphasizes the connection between observations and theory in the Lower Instability Strip. It is argued that the $\delta$ Scuti and $\gamma$ Doradus pulsators are very close relatives in the sense that the $\gamma$ Doradus phenomenon can also be seen in the slightly hotter $\delta$ Scuti variables.

New developments and recent progress are reviewed. Arguments are given why all (or almost all) stars in the Lower Instability Strip are pulsators. Furthermore, the question of the so-called missing modes is answered as very extensive photometry campaigns have revealed a large number of pulsation modes with amplitudes less than one millimag. Arguments are given that the 500+ $\ell$ = 0 to 2 modes predicted for $\delta$ Scuti stars are actually present.

The progress made in developing reliable methods of pulsation mode identification is briefly discussed. The discovery of many close modes with small amplitudes sets severe requirements concerning the length of future studies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss the results of a systematic search for multi-periodic pulsations in Galactic Bulge δ Scuti and RR Lyrae stars. Six “normal” double-mode variables pulsating in two radial modes have been identified (5 δ Scuti-type and 1 RR Lyrae-type). In 37 RR Lyrae stars secondary periodicities very close to the primary pulsation frequency have been detected. These periodicities correspond to nonradial modes of oscillation. They are found in ∼ 23% of RRab and in ∼ 3% of RRc variables of our sample.

Many late WC type Wolf-Rayet (WR) stars are known to form dust in their winds. While, in the case of episodic dust makers, it is now clear that dust formation takes place due to a colliding wind phenomenon, we still do not know for sure if binarity is the main reason for dust formation in persistent dust makers. This work is to understand, if persistent dust formation is also due to colliding winds in close binary systems. A systematic search for colliding winds is taken up via high resolution spectroscopy of the He i λ1.083μm emission line. Preliminary indications of binarity in many persistent dust makers are seen.

High S/N spectroscopic studies of the abundance patterns characterizing extremely metal-deficient halo field stars and globular cluster stars have served to provide significant clues to and increasingly stringent boundary conditions upon the chemical evolution of the halo population of our galaxy. Guided by our current knowledge of nucleosynthesis as a function of stellar mass occurring in stars and supernovae, we identify some interesting constraints that these combined observational and theoretical considerations impose upon theories of the early history of our galaxy.

The stars HD 224638 and HD 224945 belong to the new class of F0 V spectral type stars which show an unusual kind of variability for that region of the HR diagram (Mantegazza et al. 1993).

The variability of these two stars has been discovered and studied by Mantegazza, Poretti & Zerbi (1994). They show small amplitude light variations with characteristic time scales of the order of one day. The light curves are not periodic and it is difficult to satisfactorily fit them even with several periodic terms.

In order to explain our 1991 B colour observations we tentatively suggested that in both stars two close periodic terms were present with a characteristic frequency of about 0.8 c/d, and that these terms had a double wave shape for HD 224638 and a triple wave one for HD 224945.