bluuebunny/crossref_metadata_2025 huggingface dataset:
The Search for the Elusive Companion of EG Andromedae
Authors: Pesce Joseph E. , Stencel Robert E. , Oliversen Nancy A.
Published: July 2016

We report observations at opposite quadratures of the interacting symbiotic binary EG Andromedae (HD 4174, Period = 470d). Correcting for absolute motion at the system, it appears that many of the nebular lines arise from material that moves with the red giant star. The He II feature appears to track the hot component. It may be possible to use this feature in other, similar systems in order to “pin-down” the mass ratio.
Effects of Eccentric Orbit of BF Cygni on IUE and Optical Spectra
Authors: Mikolajewska J. , Mikolajewski M.
Published: July 2016

A recent analysis of all available photometric data has resulted in a new ephemeris for BF Cyg: MIN=JD 2415058 + 756.8E. Simultaneously, optical spectra collected in 1979–1986 showed periodic changes of all emission lines (Mikolajewska 1987; Mikolajewska & lijima 1987). It is interesting that the forbidden lines of [OIII] varied in antiphase to the permitted emission lines and optical brightness.

IUE spectra taken in 1979–1981 showed a strong hot continuum and high ionization resonance emission lines of NV, SilV CIV, intercombination lines of NIV], NIII], SiIII], CIII] and OIII] as well as Hell emission. The observed λ2200Å interstellar absorption band suggests E(B-V)≃0.3. Taking into account the interstellar reddening distribution in the vicinity of BF Cyg (Lucke 1978; Mikolajewska & Mikolajewski 1980), the observed extinction implies a distance d≲1.5kpc. This distance is in good agreement with the observed low value of the systemic radial velocity (∼15 km/s, Fig.1) of BF Cyg and the standard galactic rotation law. The standard extinction curve with E(B-V)=0.3 (Seaton 1979) was used for reddening correction of the spectra. The UV continuum of BF Cyg can be interpreted as a combination of a hot subdwarf (Teff≃60000K, L≃2500L⊙ for d=1.5kpc) and hydrogen bf+ff emission (Te≃10000K). The emission measure of the nebular (bf+ff) continuum varied from ∼4×1059cm−3 at maximum to ∼1059cm−3 at minimum. Assuming cosmic abundance of Si/C the observed SiIII]/CIII] line ratio implies ne≃2×l010cm−3 at the photometric maximum and ne≃3×109cm−3 at the minimum. We assume that these values are representative of the region where the bulk of the HI Balmer and intercombination line emission is produced. The ratio of NV(1240)/NIV(1720) gives Te(NV)≃11500K close to the value derived for the Balmer emission region from the UV continuum fit.
A Comparison of Luminosity Calibrations for MK Classifications of OB Stars
Authors: Lesh Janet Rountree
Published: July 2016

It has been apparent for some time that there is a need for a single luminosity calibration to be used with modern MK types for early-type stars, at least from 0 through middle B. The widely used calibration of Blaauw (1963) has to be replaced because the refinement of the MK system - as reflected in the large collections of spectral types by Lesh (1968), Hiltner, Garrison, and Schild (1969) and Walborn (1971) - has led to a lower mean luminosity for most main sequence subgroups of early-type stars, as the higher luminosity stars tend to move out of class V. Thus the calibrations of Lesh (1968) and Walborn (1972, 1973) are systematically fainter than Blaauw’s
Spectral Morphology in Southern open Clusters and Associations at La Plata Observatory
Authors: Levato H. , Malaroda S.
Published: July 2016

Our purpose is to describe the program on spectral classification of members of open clusters and associations started in January 1977 at La Plata Observatory. The program is essentially a continuation of the Abt and Levato studies made from Kitt Peak so, many details of it have been already described in Dr. Abt’s paper in this volume. We have a list of 40 clusters and associations included in the program which consists in obtaining two sets of spectra in two dispersions, 39 Å/mm and 125 Vmm, both sets 1.2 wide. These spectra, as has already been mentioned, are very useful for deriving accurate MK types and for discovering peculiar stars.
Spectea of Of and Be Stabs in the near Infrared Region up to 1.1μ
Authors: Andrillat Yvette
Published: July 2016

The classification of Of stars presents a number of problems, in part due to the small interval of the spectrum explored up to now. With J.M. Vreux an extended study has been made in the infrared region, up to 1.1μ. Be stars have been studied with L. Houziaux, The hydrogen Paschen lines and lines of helium I and II can be studied in the region and used to determine temperature class and luminosity.
Medium Resolution Spectroscopy at 1-2 Microns
Authors: Mould J. R.
Published: July 2016

The need for establishing classification criteria at long wavelengths is stressed. The usefulness of doing this is illustrated with a discussion of the composite spectra of FU Orionis stars. Spectra of these pre-main-sequence stars from 1.5-2.5μ were obtained with a Fourier Transform Spectrometer. Luminosity criteria in the l-2μ range are also discussed with application to M stars.
Spectral Classification from Low Dispersion Objective Prism spectra taken with the UK 1.2m Schmidt Telescope
Authors: Nandy K.
Published: July 2016

A thin prism (with a dispersion of 2480 Å/mm at Hγ and Hβ) is now available for the UK 1.2m Schmidt telescope. Å 60-min. unwidened exposure on a Ilia-J (hypersensitized) emulsion reaches fainter than 20 mag. The spectra are measured and digitised with the fast measuring machine COSMOS. A method to determine the red shift of faint galaxies and the spectral classes of faint stars and galaxies from the digitised spectra will be described.
Slitless Spectroscopy of Stars with Grating-Prism and Focal Reducer Techniques
Authors: Geyer E. H.
Published: July 2016

A slitless field spectrograph for Cassegrain telescopes has been designed. It is based on the focal reducer optical arrangement and grating prisms. Together with the “multiple diaphragm method” not only a gain in limiting magnitude of 3 to 4 magnitudes has been achieved, but also other drawbacks of the classical objective prism camera are avoided.
Two Dimensional Spectral Classification Using a Computer
Authors: Zekl H. , Appenzeller I.
Published: July 2016

A computer program for the automatic classification of stellar spectra is described. The aim of this program is to derive accurate absolute luminosities and spectral classes of individual stars for improved spectral parallaxes. Preliminary results are presented and future applications are discussed.
Empirically Oriented Approach to Spectral Classification
Authors: Vardya M. S.
Published: July 2016

It is stressed that the ultimate aim of spectral classification is stellar classification. MKK classification is briefly described and possible additional parameters or dimensions discussed. Considering various new developments, a new approach to classification which is highly computer dependent, is suggested.
On the Practical Application of the MK and Related Spectral-Classification Systems to Spectrograms of Various Resolutions
Authors: Ardeberg A.
Published: July 2016

For MK classification of program field stars the “normal” observer is confronted with a number of practical problems, rendering classification on the true MK system very difficult. These problems concern completeness of standard-star grid, spectrogram resolution, comparison of originals-reproductions, spectrogram density levels, spectrogram widening and emulsion. A new atlas of slit spectrograms at 74 Å mm−1 is presented, giving good coverage especially for high-luminosity stars. MK classification from spectral intensity tracings is discussed. Advantages include easy distribution and sharing of standards, relaxation of resolution requirements and wide acceptable density range. Apparent shortcomings of the method seem easy to overcome. An atlas of spectral intensity tracings is presented. Some problems regarding objective-prism classification are discussed for higher as well as lower resolution. Quantitative classification methods are commented. Work in progress is presented on systems for two-dimensional classification of low-resolution objective-prism spectrograms of stars with spectral types earlier than G0.
Ultraviolet Classification from the S2/68 Experiment on Board the Tdia Satellite
Authors: Cucchiaro A.
Published: July 2016

A morphology analysis as well as a statistical study of the spectra provided by the S2/68 experiment is made in order to establish ultraviolet criteria of classification. These criteria, either line features or intensity ratios, permit the establishment of a two-dimensional classification to be made from the so-called B0 to G0 type star in the classic range. This classification scheme permits also “abnormal” spectra to be singled out, thanks to the definition of the “normal” spectra.
The Periods of Cataclysmic Variables
Authors: Herczeg T.J.
Published: July 2016

The present status of the period studies of cataclysmic variables is briefly reviewed, mainly from the observational point of view. A few comments on individual objects include EM Cyg, Z Cha, WZ Sge and AM CVn.
Discrepant Measurements of the Radial Velocities of SS Cygni: Solution to the Problem
Authors: Robinson E.L.
Published: July 2016

We show that the discrepancies among the various measurements of the radial velocity curve of the K5 V star in the dwarf nova SS Cyg have been caused by (1) poor choices of lines for measuring its velocity and (2) large distortions in its velocity caused by heating from the white dwarf and its accretion disk. The correct K velocity of the center of mass of the K5 V star is 158 ± 3 km s−1.
Periodic Variations in the Spectrum of the Dwarf Nova WX Hyi in Outburst and Minimum
Authors: Vogt N. , Curé M.
Published: July 2016

We present the analysis of spectrograms obtained during quiescence and during an ordinary outburst of the SU UMa type dwarf nova WX Hyi (ESO 3.6m telescope, B&C spectrograph with Image Disector Scanner, 171 Åmm−1, range 4000–7000 Å, time resolution 6min.). The radial velocities of these spectra have been discussed by Schoembs and Vogt (1981) who also derived the orbital elements of WX Hyi. The phases φmax refer to these elements. All velocities discussed here are with respect to the white dwarf, not to the center of mass of the binary system.

In quiescent state we did not find significant radial velocity variations. The equivalent widths Wλ of the He I emission lines revealed periodic variations with an amplitude of ≈30%, maximal values of Wλ were observed at φmax = 0.0... 0.2. In contrast, the equivalent widths of the Balmer lines were not variable.

During outburst we found periodic radial velocity variations of the emission peak of Hα, Hβ and He I 5875 with an amplitude of ≈100 km s−l, φmax ≈ 0.5. Also the broad Balmer absorption lines revealed periodic radial velocity variations, with a similar amplitude (φmax = 0.3...0.5). The equivalent width of the Hα central emission peak varies with an amplitude of ≈30%, φmax ≈ 0.85. No variations of the equivalent width of the Balmer absorption lines were found.

The outburst observations suggest that the preceeding part of the disc is brighter than the following one (in orbital motion). This is probably due to heating of the preceeding part by collisions with circumbinary matter, which seems to have an enhanced density in outburst as compared to the quiescent state. The emission lines are formed in outer layers or in a halo around the disc. The equivalent width variations can be interpreted in terms of interactions between this halo and the optically thick part of the disc.

A more detailed discussion of the data is being published elsewhere.
Ultraviolet Observations of Cataclysmic Variables
Authors: Verbunt F.
Published: July 2016

The preliminary results of the analysis of more than 1000 spectra of cataclysmic variables in the archive of the International Ultraviolet Explorer were presented at the meeting. To characterize the slope of the spectra I use F = log(f1460Å/f2880Å). For most spectra F lies between 0.2 and 0.7. No correlation of F with orbital period, inclination, system type or (for dwarf novae) length of the interoutburst interval are found, apart from somewhat lower values of F for DQ Her type systems. Out of 16 dwarf novae for which spectra both at outburst maximum and minimum are available 11 show no large difference in F between maximum and minimum, and in 5 F declines with the flux level. Out of 6 dwarf novae 5 show very red spectra during the rise to maximum, and 1 shows slopes during rise similar to those during decline.

In the ultraviolet resonance lines, due to a wind from the disc, no correlation is found between inclination and terminal velocity.
IUE Observations of HL CMa and the Winds of Cataclysmic Variables
Authors: Mauche C.W. , Raymond J.C.
Published: July 2016

As evidenced by the P Cygni profiles of their ultraviolet resonance lines, cataclysmic variables—like early-type stars—are known to have extensive, high velocity winds. Assisted by AAVSO visual data and IUE ultraviolet spectra, we present an observational and theoretical study of the P Cygni profiles of the dwarf nova HL CMa. As these profiles are dependent upon the ionization structure of the wind, we describe a model of a radiatively-driven shocked wind for cataclysmic variables, and present results for the temperature and ionization structure of the outflowing gas.
Explosion of White Dwarfs
Authors: Lopez R. , Isern J. , Labay J. , Canal R.
Published: July 2016

We present models for Type I supernova light curves based on the explosion of partially solid white dwarfs in close binary systems. Studies of such explosions show that they leave bound remnants of different size. Our results reproduce quite well the maximun luminosities, the expansion velocities and the shape of the light curve. As the two basic papameters that govern the light curve, the ejected mass and the mass of 56Ni produced, are variable our models reproduce the slow and fast subclasses of “classical” Type I supernovae.
The Variable Ṁ Scenario for Nova Outbursts
Authors: Kovetz A. , Prialnik D. , Shara M.M.
Published: July 2016

An evolutionary scenario for classical novae is proposed, which is intended to solve the discrepancies that exist between theory and observations: the space densities of classical novae deduced from surveys in the solar neighbourhood are lower by about two orders of magnitude than those predicted theoretically, and the mass transfer rates in nova binaries, as estimated from observed luminosities in quiescence, are higher than those allowed by the thermonuclear runaway model for nova outbursts. These discrepancies disappear if mass transfer (at a high rate) takes place for only a few hundred years before and a few hundred years after an eruption, but declines afterwards and remains off for most of the time between outbursts. We show that such a behavior is to be expected if one takes into account the variation of binary separation, due to mass ejection on the one hand and angular momentum losses on the other hand.

One of the aspects of this scenario, on which we report in more detail, is the possibility of enhanced Roche-lobe overflow of the secondary, due to its expansion that results from irradiation by the high nova luminosity. We followed the evolution of a 0.5M⊙ main sequence star illuminated by a changing flux, typical of a classical nova. The numerical results indicate that, in spite of the slight binary separation that may occur after eruption, mass loss from the irradiated and thus bloated secondary should continue for a few hundred years. Other aspects of the variable Ṁ scenario are briefly summarized.
The Frequency of Novae in the Galaxy
Authors: Liller W.
Published: July 2016

Recent statistics indicate that each year an average of 3.5 novae or nova-like objects are discovered in the Galaxy. With reasonable assumptions about the completeness of the surveys, we arrive at an overall galactic production rate of 76 ± 38 y−1. When recurrent novae are omitted, this rate drops to 60 + 30 y−1. Hence, it seems that our Galaxy is more prolific than M31 in nova production. The total amount of material released into galactic space by novae each year is about one-tenth that ejected by supernovae.
Accretion in Magnetic Cataclysmic Variables
Authors: Hameury J.M. , King A.R. , Lasota J.P. , Ritter H.
Published: July 2016

We discuss the arguments in favour of the suggestion that polars (AM Her systems) and intermediate polars (IP’s) have magnetic fields of the same order of magnitude, and form one single class of objects. The period distribution of magnetic cataclysmic variables is well explained if they evolve the same way as non magnetic systems, IP’s becoming AM Her systems after crossing the gap. We discuss some consequences of the limited magnetic moment distribution (1033 ≤ μ ≤ 1034 G cm−3) in magnetic CV’s, in particular for the existence of accretion discs in those systems.
Time-Resolved Optical Spectroscopy of AM Her X-Ray Sources
Authors: Mouchet M. , Van Amerongen S.F. , Bonnet-Bidaud J.M. , Osborne J.P.
Published: July 2016

We present high-time resolution spectroscopy of two AM Her sources E1405−451 and E1013−477. For E1405−451, the Balmer emission lines profiles can be divided into a narrow component and a broad one. The amplitudes of the radial velocity curves of these components are respectively 265±30 km/s and 390±50 km/s. The orientation of the column determined from polarimetry is not compatible with the broad component being formed in the lowest parts of the column. Photometric and spectroscopic results on E1013−477 do not confirm the previous reported 103 min. period. Rapid variability (<1.5h) as well as long term modulation (>3.3h) is present in these data.
Optical and UV Observations of the Intermediate Polar 3A0729+103. Modulation with the Orbital Period
Authors: Falomo R. , Bonnet-Bidaud J.M. , Charles P.A. , Maraschi L. , Mouchet M. , Mukai K. , Tanzi E.G. , Treves A.
Published: July 2016

3A0729+103 (= BG CMi) is an intermediate polar discovered through its X-ray emission (McHardy et al. 1981, 1984). The orbital period is 3.235 hours and the rotation period is 15.2 minutes, For ephemeris and references on the source we refer to McHardy et al. (1984). We report here on optical (4025 to 5090 A) and ultraviolet (1200 to 3200 A) spectroscopy obtained, respectively, on Dec 1, 1984 and April 21, 1985. Our data show clear modulation of spectral features with the orbital period.
Rapid Mass Accretion on a Fully Convective Star
Authors: Sarna M.J. , Ziólkowski J.
Published: July 2016

We investigated the effects of rapid mass accretion on a fully convective main sequence star of 0.3 M⊙, taking into account the heating of its photosphere by the kinetic energy of the infalling matter. We found that the star develops highly inhomogeneous structure consisting of almost unperturbed initial convective core and a radiative envelope composed of the accreted matter. Both regions are separated by a very stable temperature inversion layer. Due to such structure accreting convective star may significantly increase its radius (contrary to earlier suggestions).
Hydrogen Depletion and the Evolution of Cataclysmic Variables to Low Mass X-Ray Binaries
Authors: Williams R.E. , Phillips M.M. , Heathcote S.R.
Published: July 2016

Certain cataclysmic variables may evolve into low mass X-ray binaries if the white dwarfs can steadily accrete sufficient mass to exceed the Chandrasekhar limit. We present spectra of a recurrent nova and a low mass X-ray binary which are very similar to each other, and are also unusual for the strengths of the observed He II emission. We suggest that this similarity is not coincidental, but is evidence for an evolutionary link between the two classes of objects. A hydrogen depletion in the accreting gas is implied from the emission line fluxes, and may be an important parameter in determining whether accreted gas remains bound to the white dwarf, enabling eventual core collapse to occur.
X-Ray and Optical Observations of the X-Ray Source EX0020528+1454.8
Authors: Hudec R. , Wenzel W. , Goetz W. , Valníček B. , Peřestý R. , Richter G.A. , Hacke G. , Huth H. , Mrkos A. , Tremko J.
Published: July 2016

We present preliminary results of the EXOSAT X-ray observations and quasisimultaneous and simultaneous optical photometry of the X-ray source EX0020528+1454.8 = 1E0205+149 found independently as an serendipitous source both with Einstein and EXOSAT satellites. The optical counterpart is a pair of dMe stars, Our results indicate that the object is variable both in X-rays and optical wavelenghts, and probably belongs to dMe flare stars.
IUE Observations of CH Cygni Continuum during 1979–1986
Authors: Mikolajewska J. , Selvelli P.L. , Hack M.
Published: July 2016

Variations of the UV continuum have been analyzed. The observed UV continuum may be reproduced by a superposition of a Kurucz model atmosphere (log g=2), Teff~ 8500 - 15000 K) and optically thin hydrogen bound-free and free-free emission (Te~ 1000 K). The temperature of the Kurucz atmosphere is the lowest at the maximum of brightness. The flat minimum in the UV integrated flux was observed in May-October 1985.
Exosat and IUE Observations of the Symbiotic Binary R Aquarii during Maximum and Minimum
Authors: Viotti R. , Piro L. , Friedjung M. , Cassatella A.
Published: July 2016

Coordinated IUE and EXOSAT observations of the symbiotic Mira R Aqr, made in June and December 1985, at phases 0.0 and 0.5 of the Mira light curve, are discussed. A weak X-ray flux has been for the first time unambiguously detected without any significant change with the Mira light curve. Also the UV spectrum of the central object has not varied, while the presence of high ionization lines (NV and HeII) in the spectrum of the jet-like feature is confirmed. The data are discussed in the light of a model in which the jet is preexisting material illuminated by the recently increased X and UV radiation from the inner edge of the accretion disk around the degenerate companion of the Mira primary.
The Characteristics of Ancient China’s Astronomy
Authors: Zezong Xi
Published: July 2016

What are the characteristics of ancient China’s astronomy? Many scholars have discussed the problem. In 1939 Herbert Chatley summed up fifteen points. Joseph Needham(1959) in his great work Science and civilisation in China concentrated it into seven points.

1

the elaboration of a polar and equatorial system strikingly different from that of the Hellenistic peoples;

2

the early conception of an infinite universe, with the stars as bodies floating in empty space;

3

the development of quantitative positional astronomy and star catalogues two centuries before any other civilisation of which comparable works have come down to us;

4

the use in these catalogues of equatorial coordinates, and a faithfulness to them extending over two millennia;

5

the elaboration, in steadily increasing complexity, of astronomical instruments, culminating in the 13th century invention of the equatorial mounting, as an ‘adapted torquetum’ or ‘dissected’ armillary sphere;

6

the invention of the clock drive for that forerunner of the telescope, the sighting tube, and a number of ingenious mechanical devices ancillary to astronomical instruments;

7

the maintenance, for longer continuous periods than any other civilisation, of accurate records of celestial phenomena, such as eclipses, comets, Sunspots, etc.
Revision of Yugas and Yuga-Constants in Indian Astronomy
Authors: Sarma K.V.
Published: July 2016

Among the historians of Indian astronomy, John Bentley seems to be first to stress, nearly two hundred years ago, that yuga and kalpa, which form the basic time-divisions used for traditional astronomical computations in India, are not historical but astronomically interpolated. Bentley says that a division of time simply into the four yugas, viz. Krta, Tretā, Dwāpara and Kali, was introduced in 204 B.C. “It appears,” as Bentley surmises, “that at, or about this period (204 B.C.), improvements were made in astronomy; new and more accurate tables of the planetary motions and positions were found, and equations introduced. Beside these improvements, the Hindu history was divided into periods, for chronological purposes....The period immediately preceding the inventor was called the first, or Kali yuga; the secojid or next, was called the Dwāpara Yuga; the third was called the Tretā Yuga; and the fourth, or furthest back from the author, was called Kṛta Yuga and with which the creation began. The end of the first period, called Kali was fixed by a conjunction of the Sun, Moon and Jupiter, in the beginning of Cancer, on the 26th June 299 B.C. This was called the Satya Yuga, or true conjunction, and is the radical point from which the calculation proceeds” (Bentley 1823, p.61-62).
Indian Calendars
Authors: Chatterjee S.K.
Published: July 2016

The first treatise on calendric astronomy was compiled C1300 B.C.and is known as “The Vedāṅga Jyautiṣa. It gives rules for framing calendar covering a five-year period, called a ‘Yuga’. In this yuga-period calendar, there were 1830 civil days, 60 solar months, 62 synodic lunar months, and 67 sidereal lunar months. The calendar was luni-solar, and the year started from the first day of the bright fortnight when the Sun returned to the Delphini star group. Corrections were made, as required, to maintain this stipulation to the extent possible. The Vedāṅga calendar was framed on the mean motions of the luminaries, the Sun and the Moon, and was based on approximate values of their periods. Vedāṅga Jyautiṣa calendar remained in use for a very long time from C 1300 B.C. to C 400 A.D. when Siddhānta Jyautiṣa calendar based on true positions of the Sun and the Moon came into use and gradually replaced totally the Vedāṅga calendar.
On the Solar Model and the Precession of the Equinoxes in the Alphonsine Zīj and its Arabic Sources
Authors: Samsó Julio
Published: July 2016

Alphonse X, King of Castille (1252-1284), sponsored astronomical work previous to the compilation of the Alphonsine Tables, carried out by his two Jewish collaborators Yehudah ben Mosheh and Isaac ben Sid. On the one hand, these tables can be considered the first European attempt to develop original research in astronomy, but on the other hand, an analysis of this work should be concerned, first of all, with its Islamic precedents. This is why I tend to consider the Alphonsine Tables as another zīj which should be studied in the light of what we know concerning the development of Islamic zījes in Medieval Spain. Of these, two seem to be well documented as having been known and used by the Alphonsine collaborators. One of them is al-Battānī’s zīj, the canons of which were translated into Spanish (Bossong, 1978), and which may have been used to compute the solar positions for the end of each month appearing in four Alphonsine works (Astrolabio redondo, Cuadrante para rectificer, Relogio dell agua, and Lámina Universal). These positions have been computed, however, with the Alphonsine Tables themselves. The second zīj known in the Alphonsine circle was al-Zarqalluh’s Toledan Tables, used — as O. Gingerich has established — to compute the solar and planetary positions in the horoscope which was cast to establish the propitious moment to start the Latin translation of Ibn Abī-l-Rijāl’s Kitāb al-bāric fī ahkām al-nujūm (Hilty, 1954, lxii-lxiii).
Uses of Ancient Data in Modern Astronomy
Authors: Eddy J A.
Published: July 2016

Ancient astronomical data are a limited resource that can fill unique needs in modern research. Records from the Orient are of particular value because they were taken more or less continuously, as parts of dynastic and local histories – often for astrological purposes. We review three problems in modern astronomy that lean heavily on ancient records from the Middle East and Orient: the study of solar variability; studies of the variable rotation of the earth; and studies of the occurrence and physics of novae, supernovae and comets.
Objective Prism Surveys
Authors: McCarthy Martin F.
Published: July 2016

A survey of surveys made with objective prisms since the Hamburg Schmidt Conference in 1972 is presented. Ten outstanding achievements attained by these techniques are listed. Detailed accounts of particular surveys both general and specific follow. A table listing fundamental classical studies is given plus a list of the location and properties of the largest Schmidt-type cameras.
Remarks on T-Grain Technology Applied to Astrophotography
Authors: Maury Alain
Published: July 2016

If T-grain Technology can be used to manufacture emulsions of astrcj nomical type, it will provide a better Detective Quantum Efficiency than any existing plate. As Dr. Millikan explains us, this increase in D.Q.E. can result in an increase in Signal to Noise ratio (i.e. increase in coil trast or decrease in granularity) or in an increase of plate speed. As Kodak and we, their customers, don’t have a lot of money to spend for three or more new emulsions, we have now to choose for a new emulsion, which might be a harder one (more contrast), a finer one (better granularity), or a faster one.
Internal Calibration of Astrononomical Photographs
Authors: Bunclark P.S. , Irwin M.J.
Published: July 2016

By applying the principle that all stellar image profiles should be identical apart from a scale change, we can derive a relative calibration for a photographic plate without use of calibration spots or other indirect means.
International Halley Watch Wide Field Network for Large-Scale Phenomena, Calibration of Schmidt Plates Using Star Profiles
Authors: Klinglesmith Daniel A. , Rupp Stephen W.
Published: July 2016

The International Halley Watch Wide Field Network for Large-scale Phenomena (Niedner, Rahe and Brandt, 1982) will be receiving several thousand original or first copy images of the large scale structure of comet Halley. These images will be coming from over 90 telescopes at 70 different observatories around the world. Some but not all of the photographic material will have associated sensitometry. It is anticipated that since this network is looking for changes in the plasma tail structure most, if not all, observations will be made with unfiltered Kodak IIa0 emulsion. One of the major tasks of the network will be to study the plasma tail variations at the highest time resolution possible. In order to do this, it will be necessary to combine photographs taken at many observatories.
The 2020Gm PDS Microdensitometer at Muenster
Authors: Seitter Waltraut C.
Published: July 2016

The 2020GM PDS microdensitometer of Perkin-Elmer, Optical Division, was installed at Muenster University during the summer of 1982. The present communication summarizes the greater part of work performed during its first year of operation and outlines plans for the future. The microdensitometer and the system configuration are shown in Figs. 1 and 2.
Galactic Research With Schmidt-Telescopes
Authors: Becker Wilhelm
Published: July 2016

The use of Schmidt Telescopes for the determination of space density gradients is discussed. Space densities can be determined by a three colour photometry for main sequence stars with M< 8. 0 and later type giants of population I and for metal poor stars in higher galactic latitudes with M< 7. 0. A general synthesis of the present available results is not yet possible. But the determination of a density gradient for later type giants along a galactic radius, the distribution of metal poor stars in a galactic meridian and around the galactic centre seems to be possible with the existing observational material.
Asiago Schmidt Surveys of Variable Stars and Supernovae
Authors: Rosino L.
Published: July 2016

Survey methods used at Asiago for finding supernovae and new variable stars are reviewed. Some by-products of the supernova searching are indicated. It is shown that the use of infrared emulsions is particularly effective for the discovery of new Mira-stars in Milky Way fields.
Star Counts
Authors: Kron Richard G.
Published: July 2016

The number of stars counted along a particular line of sight depends on the spatial distribution of stars, the luminosity function, and the absorption. Thus star count programs are designed to constrain or determine one or more of these functions. Early efforts to understand the structure of our Galaxy, including the fundamentals of stellar statistics, were largely based on work that involved star counts. Since then a growing appreciation has developed for the variety of forms the density function D(r) and the luminosity function Φ(M) can take, especially the recognition of different stellar populations, each with different density and luminosity functions. In the simplest formulation two distinct populations are considered: disk and halo. This suggests two distinct formation histories, but uncertainty in the picture remains (Eggen, Lynden-Bell and Sandage 1962; Ostriker and Thuan 1975; Saio and Yoshii 1979; Jones and Wyse 1983).
High-Resolution Narrow-Field Versus Low-Resolution Wide-Field Observations of Galaxies
Authors: Capaccioli M. , Davoust E. , Lelièvre G. , Nieto J.-L.
Published: July 2016

There is an increasing evidence that small-scale phenomena occuring in the inner regions of galaxies are related to large-scale phenomena such as, e.g., merging or violent interactions between galaxies. Plausible scenarios (e.g. Rees, 1978) involve, for instance, accumulation of material from the outside along the accretion disk of a black hole and subsequent ejection in two opposite directions into the intergalactic medium. Active galaxies and QSO's may be the extreme examples of the link between large-scale phenomena contributing to the evolution of gala, xies. Moderately active or even normal galaxies are also submitted to entangled events on both scales. The aim of this communication is to illustrate the complementarity between high-resolution, small-field telescopes and Schmidt-type telescopes for the study of this phenomenology, and to stimulate further research by a few challenging examples.
Global Structure of Galaxies and Quantitative Classification
Authors: Okamura S. , Kodaira K. , Watanabe M.
Published: July 2016

We have been carrying out digital surface photometry of galaxies using the plates taken with the 105-cm Schmidt telescope at the Kiso Observatory, a branch of the Tokyo Astronomical Observatory. Two dimensional V-band luminosity distributions of 26l galaxies in the Virgo and the Ursa Major regions have been compiled so far (Watanabe et al. 1982, Watanabe 1983). They form one of the largest samples of homogeneous surface photometric data. This discourse is to draw attention to some new results, which are summarized below, on the structure of galaxies derived from the analysis of the homogeneous sample. Detailed discussion will be given elsewhere (Kodaira et al. 1983, Okamura et al. 1983, Watanabe et al. 1983). Most of the sample galaxies are members of either the Virgo or the Ursa Major Clusters, both lying at nearly equal distance (Aaronson and Mould 1983). Their morphological types range from elliptical (T=-5) to Magellanic irregulars (T=10).
Searching For Emission-Line Galaxies
Authors: Kinman T.D.
Published: July 2016

Survey methods for finding emission-line galaxies are reviewed. Observational selection effects are investigated by comparing different surveys and the limitations of the different techniques are discussed. The advantages of Ha surveys for finding low luminosity galaxies and those with low excitation emission spectra are emphasized.
Quasi Stellar Objects and Active Galactic Nuclei
Authors: Barbieri C.
Published: July 2016

The role of the Schmidt telescopes in the discovery of the Quasi Stellar Objects and of the Active Galactic Nuclei, and in the understanding of their properties was and continues to be of the greatest importance. Thousands of Radio-Sources have been quickly associated to their optical counterparts thanks to the worldwide availability of the Palomar Observatory Sky Survey plates and charts and more recently of the films of the ESO B Survey. Other thousands of QSOs and AGNs devoid of radio emission are found by the large Schmidts nowaday in operation. This wealth of data give fundamental cosmological knowledge and insight in the physical processes occuring in these objects. I'll concentrate in this Review on two specific topics, namely on the discovery techniques and on the study of the optical variability. To both subjects, the 67/92 cm Schmidt telescope here at Asiago has made significant contributions. The first topic is treated in several excellent papers, such as the one by M. Smith (1978) and the one by P. Veron (1983); the material presented in the second part is largely new. In the following, I'll use rather loosely the terms QSOs and AGNs to designate a variety of objects including Quasars (those QSOs in catalogs of Radio-Sources), high-redshift compact galaxies with emission lines, BL LACset similia.
Solar Physics from Spacelab 2
Authors: Dere K.P.
Published: July 2016

Four instruments were flown aboard the Spacelab 2 shuttle mission to perform systematic observations of the solar atmosphere at high resolution and to measure specific global properties of the sun. The Solar Optical Universal Polarimeter recorded series of white light images with which the evolution of the granulation and sunspot phenomena have been studied. The Coronal Helium Abundance Shuttle Experiment provided measurements of a number of EUV coronal lines, and, in particular, the intensities of He IIλ304 and H Iλ1216 from which the coronal helium abundance can be determined. The High Resolution Telescope and Spectrograph obtained stigmatic spectra in the 1200–1700 Å wavelength range, as well as broad band UV spectroheliograms, to provide diagnostic information on the solar chromosphere and transition zone. The Solar Ultraviolet Spectral Irradiance Monitor measured the total solar irrandiance at a resolution of 1.5 and 50 Å in the 1200 to 4000 Å wavelength range to an accuracy of 3Z.
High-Resolution Spectra and Photoabsorption Coefficients for Carbon Monoxide Absorption Bands Between 94.0 run and 100.4 nm
Authors: Yoshino K. , Stark G. , Smith P.L. , Parkinson W.H. , Ito K.
Published: July 2016

Theoretical descriptions of the abundance and excitation of CO in interstellar clouds require accurate and complete information on many molecular properties. In particular, data such as line positions, line widths, and photoabsorption coefficients, which will allow the photodissociation rate for CO to be determined, are needed. We have measured some photoabsorption coefficients for CO at a resolving power more than 20 times greater that that used in previous work. Most of our results for bands between 94.0 and 100.4 nm are larger than the values of Letzelteret al.
Charge Exchange in Laboratory and Astrophysical Plasmas
Authors: Pequignot D.
Published: July 2016

Recent experiments in tokamak plasmas demonstrate that charge exchanges manifest themselves in a wide variety of situations. It is now realized that charge exchanges involving excited states of hydrogen should be considered: these reactions represent a challenge for atomic physics, detailed plasma modeling, and quantitative plasma diagnostics. Charge exchanges between ions can in some cases modify the state of the gas and produce specific emission.

Charge exchanges are important for the ionization balance of many ions in either warm coronal plasmas or photoionized plasmas of Astrophysics. Lines produced by charge exchange have been discovered in the spectrum of nebulae and probably the solar chromosphere. Introduction of charge exchanges modifies earlier views about the structure of some astrophysical objects. The nebulae appear as valuable “laboratories” to check theoretical charge exchange cross sections at very low energy. It is suggested that the detection of charge exchange lines in the solar spectrum would provide new insights into the dynamics of the interface between the chromosphere and the corona. It is pointed out that charge exchanges between heavy particles may have significant effects in the ionization front of some nebulae.
Generation of XUV Spectra by Powerful Picosecond Laser
Authors: Nam C.H. , Tighe W. , Suckewer S. , Feldman U. , Seely J.
Published: July 2016

The development of laser action at wavelengths shorter than those of current X-ray lasers is being investigated along two fronts. In the first case, we are exploring the possibilities for laser action at 15.4 nm in Li-like AIXI and 12.9 nm in Li-like SiXII in a magnetically confined recombining plasma. Previous work on hydrogen-like carbon, CVI, led to lasing action at 18.2 nm. Recently, this has been applied to microscopy and first results from a soft X-ray laser microscope are presented. A new technique to generate shorter wavelength X-ray lasing involves the interaction of a high power laser with a preformed plasma. The Powerful Picosecond Laser (PP-Laser) System with an output power level of 20-30 GW and focussed power density of 1016- 1017W/cm2has recently become operational. The spectra of highly ionized atoms in the XUV region were recorded on a high resolution grazing incidence spectrometer for the PP-Laser beam interacting with different solid targets.
Vuv Spectra Y to Mo
Authors: Chaghtai M.S.Z.
Published: July 2016

Using R.D. Cowan’s computations (1979) and parametric calculations of Meinders et al (1982), old analyses are thoroughly revised and extended at Aligarh, of Zr III by Khan et al (1981), of Nb IV by Shujauddin et Chaghtai (1985), of Mo V by Tauheed at al (1985). Cabeza et al (1986) confirmed the last one largely.

Extensive studies have been reported of the 1–e spectra, Zr IV (Rahimullah et al 1980; Acquista and Reader 1980), Nb V (Shujauddin et al 1982; Kagan et al 1981) and Mo VI (Edlén et al 1985). Some interacting 4p54d2levels of these spectra have been reported from our laboratory, also.

Detailed spectral analyses of transitions between excited states have furnished complete energy values for J ≠ 1 levels of these spectra during 1970s and 80s. Shujauddin et al (1982) have worked out Nb VI and Tauheed et al (1984) Mo VII from our lab, while Khan et al (1981) share the work on Zr V with Reader and Acquista (1979).
Wavelengths and Energy Levels for n = 3 − 3 Transitions in F-Like Ions: Cr XVI, Fe XVIII, Ni XX and Cu XXI
Authors: Buchet J.P. , Buchet-Poulizac M.C.
Published: July 2016

On our beam-foil spectra recorded between 100 and 350 Å, we have identified the strongest 3s-3p and 3p-3d transitions of Cr XVI, Fe XVIII, Ni XX and Cu XXI. The Is22s22p53∓level energies have thus been deduced.
Advances in UV Astronomy by the IUE Satellite
Authors: Grewing M.
Published: July 2016

On 26 January 1978 the International Ultraviolet Explorer (IUE) satellite has been launched into a geosynchronous orbit. Operated jointly by NASA, ESA, and the SERC, it has since collected roughly 50.000 UV spectra of objects of widely different nature such as comets and planets orbiting the Sun, nearby cool late-type stars, interstellar matter in our own and nearby galaxies, local and distant hot early-type stars, entire galaxies, and distant quasars. Even the recent supernova SN 1987a in the Large Magellanic Cloud has been and continues to be a target for this satellite just as many other sources in the sky. A few examples have been selected to highlight some of the unique results that have been achieved through observations with the IUE.
XUV Stigmatic Polychromators
Authors: Pouey M.
Published: July 2016

In this paper we describe new STIGMATIC XUV POLYCHROMATORS specially designed for hot plasmas diagnostics. Fixed horizontal and vertical diffracted beam divergences, as well as ERECTED FLAT FIELD are allowed imorehower solutions occur for various grooves density.

In ‘GRAZING INCIDENCE ULTIMATES POLYCHROMATORS’ (UGP), the focusing is achieved by a stigmatic toroidal mirror (unit magnification), and the dispersion of the radiation, by a simple rotation of a plane type V holographic grating WORKING AT MINUS ONE MAGNIFICATION. If the point sources used to record the hologram are located at the same distance from the grating pole STIGMATIC images are located on a circle centered on the grating pole. Erected FLAT FIELD may be then considered in so far as the corresponding broadening of the line spread function is less tha the pixel size.
Diagnostic Characterization of Laser-Irradiated dot Targets
Authors: Charatis G. , Busch G.E. , Young B.K.F. , Stewart R.E.
Published: July 2016

We have conducted a series of experiments at the KMS CHROMA facility using dot spectroscopy techniques to characterize uncertainties associated with spectral line ratio models commonly applied in determining electron temperatures and densities. Temperatures determined from the slope of the H-like free-bound continuum and densities via holographic interferometry, are compared to line ratio methods. Dot targets of (typically 100µmD Mg or Al) are irradiated with 2 to 40 × 1013W/cm2of 0.53µmlight. Time and spatial gradients are resolved using 4 diagnostics: a 4-frame holographic interferometer, an x-ray streak crystal spectrograph with a spatial imaging slit, a framing crystal x-ray spectrometer, and a conventional space-resolved time-integrating crystal spectrograph used for survey and calibration purposes. Preliminary results indicate the ionization distribution of these laser produced plasmas is not steady-state which plays an important role in measuring the temperature and and density. Electron temperatures derived from line-ratio techniques, assuming steady state conditions, disagree dramatically from simultaneous measurements using the slope of the H-like continuum. Electron densities using He-like triplet to singlet line ratios also differ from densities measured interferometrically.
Support System for the 1 m ESO Active Optics Experiment
Authors: Citterio O. , Conti G. , Mattaini E. , Franza F.
Published: July 2016

The aim of this paper is to describe the support system which has been realized for the 1 m ESO active optics experiment. This experiment has been conceived in order to verify on a smaller scale the concept of the active optics, which is foreseen for the ESO NTT 3.5 m telescope. This concept has been widely discussed in references (1) (2) (3).

For the purpose of completeness we will briefly summarize here the basic concept of the experiment, while we will describe in detail the support system and the characterization of the force actuator.
How to Quantify Ripple
Authors: Geib H. , Kühne C. , Morgenbrod E.
Published: July 2016

Every manufacturer of large mirrors is familiar with the fact that the polishing process may not only lead to large-area surface errors, such as astigmatism or spherical aberration, but also to short-period errors. In particular, this applies to aspherical surfaces because they require polishing tools of small dimensions, as compared with the mirror diameter. These errors are not entirely irregular and may therefore not be treated as statistical errors; nor are they sufficiently regular to be described in terms of amplitudes of ZERNIKE polynomials as it is now ussually done in the case of large-area aberrations (F.FRANZA e. a. 1977). Unfortunately this still is true if very high radial and tangential orders are involved, e.g.in D. ANDERSON e.a.1982. The reason is quite obvious: The description by means of ZERNIKE polynomials is based on the assumption of a two-dimensional regularity which simply does not exist in practice.
The Use of the MMT for Interferometric Imaging
Authors: Beckers Jacques M. , Hege E. Keith
Published: July 2016

We describe recent progress with interferometric imaging using the Multiple Mirror Telescope (MMT). All six telescopes can now be phased over a wide field of view simultaneously resulting in a (u, v) plane coverage corresponding to that of a 686 cm aperture telescope. We describe the open-loop phasing control of the MMT for gravitational changes and we describe a concept of an internal cophasing/coalignment system for MMT type telescopes.