The Knorre astronomers' dynasty

We attempt to throw light upon the poorly known astronomical dynasty of Knorre and describe its contribution to astronomy. The founder of the dynasty, Ernst Christoph Friedrich Knorre (1759–1810), was born in Germany in 1759, and since 1802 he was a Professor of Mathematics at the Tartu University, and observer at its temporary observatory. He determined the first coordinates of Tartu by stellar observations. Karl Friedrich Knorre (1801–1883) was the first director of the Naval Observatory in Nikolaev since the age of 20, provided the Black Sea navy with accurate time and charts, trained mariners in astronomical navigation, and certified navigation equipment. He compiled star maps and catalogues, and determined positions of comets and planets. He also participated in Bessel's project of the Academic Star Charts, and was responsible for Hora 4, published by the Berlin Academy of Sciences. This sheet permitted to discover two minor planets, Astraea and Flora. Viktor Knorre (1840–1919) was born in Nikolaev. In 1862 he left for Berlin to study astronomy. After defending his thesis for a doctor's degree, he went to Pulkovo as an astronomical calculator in 1867. Since 1873 Viktor worked as an observer of the Berlin Observatory Fraunhofer refractor. His main research focussed on minor planets, comets and binary stars. He discovered the minor planets Koronis, Oenone, Hypatia and Penthesilea. Viktor Knorre also worked on improving astronomical instrumentation, e.g. the Knorre & Heele equatorial telescope mounting (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Karl Knorre,the first astronomer of Nikolaev Observatory (on the occasion of his bicentenary)

Karl Friedrich Knorre (1801–1883) was the son of Ernst Knorre, an astronomy professor at Dorpat university. During his education at Dorpat university, he became acquainted with Wilhelm Struve, the future director of Pulkovo observatory. Because of Knorre's passion for astronomy, Struve recommended him to the post of director of the planned naval observatory in Nikolaev. From its foundation in 1821, Karl Knorre was director of the Nikolaev Naval (and later Astronomical) Observatory. He carried out star position observations with the meridian circle, worked as an astronomy instructor for sea navigators, compiled the fifth section of the star charts of the Berlin Academy of Sciences and lead all hydrographic determinations on the Azov and Black seas. In 1871, Karl Nikolaev Observatory, and moved to Berlin.     

Helium 10830 Å measurements of the Sun

Measurements of the Sun in the near-infrared He i 10830 Å absorption line were performed using the echelle spectrograph with a dispersion of 6.71 mÅ per pixel at the Vacuum Tower Telescope (German Solar Telescopes, Teide Observatory, Izaña, Tenerife, Spain) on May 26, 1993. These measurements were compared with full-disc soft X-ray images of the Sun (Japanese solar satellite Yohkoh), full-disc solar images in H (Big Bear Solar Observatory), full-disc solar images in the He i 10830 Å line (National Solar Observatory, Kitt Peak) and with full-disc microwave solar maps at 37 GHz (Metsähovi Radio Research Station). In the He 10830 Å line the Sun displays a limb darkening similar to that in the visible part of the spectrum. Active regions and H filaments show a strong absorption in the He 10830 Å line, whereas the absorption is weak in coronal holes.     

The high altitude observatory of the national center for atmospheric research Boulder,Colorado

Summary The High Altitude Observatory attempts to carry out a balanced program of theoretical and experimental research in solar, solar-terrestrial, and stellar-related physics. The scientific efforts are carried out within a sectional structure including the major areas of Solar Atmosphere and Magnetic Fields, Coronal/Interplanetary Physics, and Solar Variability. As one division of a National Center, the Observatory attempts to provide leadership through operation and sponsorship of seminars on specialized topics and organization of workshops to exploit data collections. In addition to the examples given, the Observatory, under NASA sponsorship, has organized a workshop series on solar flares, a central theme of which was the interpretation of Skylab results. This effort has resulted in the publication of a volume Solar Flares, edited by P. Sturrock, Colorado Associated University Press, 1979. Through these efforts, and the participation of individual staff members on advisory committees and working groups within the national and international framework, the Observatory continues to play a role in the guidance of research in solar and related physics.     

Emission spectrum of hot R OB star MV Sgr

The new spectroscopic observation of MV Sgr obtained at ESO in 1987 July shows enhanced emission lines of He I λ3889, [SII] λ4068 relative to the observations discussed by Jeffreyet al. (1988). The presence of [SII] λ4068 indicates the presence of planetary-nebulae-like envelope around the star. Although the radial velocity of the absorption lines and Fe II emission lines do agree with the velocity given by Jeffreyet al., the [SII] λ4068 and probably He I emission lines appear to behave differently. Based on observations collected at the European Southern Observatory, La Silla, Chile.     

Absolute calibration of solar radio flux density in the microwave region

The absolute calibration of solar radio flux density in the microwave region, which showed considerable discrepancies until 1966, has become completely uniform through international cooperative work. A complete history is described to avoid confusion, and correction factors are derived to convert the published values into absolute values for long series of routine observations. It is also shown that the most reliable calibration can be made by using a large pyramidal horn and by using sky and room temperature as calibration standards.Abbreviation of Stations for Table II, Figures 2 and 3 BERL Heinrich-Hertz-Institut, Berlin Adlershof - BORD The Observatory, the University of Bordeaux - GORK Radiophysical Research Institute, Gorky - HIRA Hiraiso Radio Observatory - HUAN Geophysical Institute of Peru, Huancayo - IRKU Irkutsk Radioastronomical Observatory - KIEL Radio Observatory, Kiel University - Radio Observatory, Kiel University - KSLV Kislovodsk Radioastronomical Observatory - MANI Manila Observatory - ONDR Ondejov Observatory - OTTA National Research Council, Ottawa - PENT Dominion Radioastronomical Observatory, Penticton - SANM Observatory of Cosmic Physics, San Miguel - SAOP Mackenzie University, Sao Paulo - SGMR Sagamore Hill Radio Observatory - SYDN University of Sydney - TOKO Tokyo Astronomical Observatory - TYKW Toyokawa Observatory, Nagoya University - UCCL Belgian Royal Observatory, Uccle     

Investigation of atmosphere nonstationarity in the supergiant 55Cyg. I. Temporal line profile variability

The CCD spectra taken with echelle spectrographs of the 2-m telescope of the Shemakha Astrophysical Observatory of the National Academy of Sciences of Azerbaijan and the 1-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences are used to study the line profile variations in the spectrum of the hot supergiant 55Cyg. The variability of the radial velocity and profiles of the lines of heavy elements is shown to be due to radial pulsation type motions. The corresponding variations for He I lines are due to nonradial pulsations. In the case of the H _β and H _α lines the pattern and behavior of variations differ for different observing periods. The variability of these lines is mostly due to the photometric and positional variability of the absorption and emission components of their profiles. The profiles of these lines show additional emission components, which move from the blue toward the red line wing. Such a behavior is indicative of the clumpy structure of the stellar envelope.     

Orbital parameters of the high‐mass X‐ray binary 4U 2206+54

We present new radial velocities of the high‐mass X‐ray binary star 4U 2206+54 based on optical spectra obtained with the Coudé spectrograph at the 2 m RCC telescope of the Rozhen National Astronomical Observatory, Bulgaria in the period November 2011–July 2013. The radial velocity curve of the He I δ6678 Å line is modeled with an orbital period P_orb = 9.568 d and an eccentricity of e = 0.3. These new measurements of the radial velocity resolve the disagreements of the orbital period discussions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the further observations ofB E /shell star V 923 Aql

V 923 Aql is one of the candidateB _E stars to be a binary star. In this research, optical and near-infrared spectral measurements of V 923 Aql is presented. V 923 Aql presents variable H Balmer line profiles with shell components. H profiles present R/V, E/C and radial velocity variation. Shell parameters of the envelope are calculated.Near infra-red and optical spectra obtained from Haute-Provence Observatory and bibliographic data obtained from SIMBAD database of C.D.S., Strasbourg Observatory, France.     

2005 Photometric observations and multiple frequencies of the <Emphasis Type="Italic">δ</Emphasis> Scuti variable V350 Peg

We present the V light curves of δ Scuti type variable V350 Peg, obtained between August and October 2005 at the Ankara University Observatory (AUG) and the TüBíTAK National Observatory (TUG). By application of multiple-frequency analyses using Period04 to 7878 photometric V measurements (which are consist of our 747 V data and 7131 V data obtained at Monegrillo Observatory) of V350 Peg, a five-frequency solution was found to be fitted well to the data. In accordance with the computed Q values for V350 Peg, it was found that this star has probably radial mode with l=0 and g-mode oscillations.     

Trigonometric parallaxes of 29 stars with large proper motions

While implementing the first stage of the Pulkovo program of research on stars with large proper motions, we determined the trigonometric parallaxes of 29 stars (12 ^m < V < 16 ^m ) based on CCD observations with a 26-inch refractor. The mean standard error was 3.7 mas. Comparison of the Pulkovo parallaxes with those obtained at the Observatory of the Yale University and the US Naval Observatory (USNO) has shown that the parallax differences (Pulkovo-Yale/USNO) lie within the limits of their measurement errors in an overwhelming majority of cases. On average, they are −0.6 ± 1.0 mas. No systematic dependences on stellar distance, magnitude, and color in this set of differences have been found. Our comparisons show that the observing and data reduction techniques used in the Pulkovo program of research on fast stars allow highly accurate trigonometric parallaxes of these objects to be obtained. All program stars are within 50 pc of the Sun; most of them belong to the immediate solar neighborhood (D < 25 pc). For two stars (J0522+3814 and J1202+3636), the trigonometric parallaxes have been determined for the first time.     

The nebular phase spectra of SN1993J

From June 19 to August 27, using the 2.16m telescope in the Beijing Astronomical Observatory, we obtained some low resolution spectra of SN1993J. The forbidden emission lines [O I], [Ca II] were very strong and dominated the spectra. However, the H and He lines were very weak. Many fine structures appeared in the H and [O I] lines. We found that the supernova had entered the nebular phase and strong instability and chemical mixing had occurred in the ejecta.     

Oral Histories in Meteoritics and Planetary Science – XVII: Joseph Goldstein

Abstract– In this interview, Joseph Goldstein ( Fig. 1 ) recounts how he became interested in meteorites during his graduate studies working with Robert Ogilvie at MIT. By matching the Ni profiles observed across taenite fields in the Widmanstätten structure of iron meteorites with profiles he computed numerically he was able to determine cooling rates as the meteorites cooled through 650–400 °C. Upon graduating, he worked with a team of meteorite researchers led by Lou Walter at Goddard Space Flight Center where for 4 years he attempted to understand metallographic structures by reproducing them in the laboratory. Preferring an academic environment, Joe accepted a faculty position in the rapidly expanding metallurgy department at Lehigh University where he was responsible for their new electron microprobe. He soon became involved in studying the metal from lunar soils and identifying the metallic component from its characteristic iron and nickel compositions. Over the next two decades he refined these studies of Ni diffusion in iron meteorites, particularly the effect of phosphorus in the process, which resulted in superior Fe‐Ni‐P phase diagrams and improved cooling rates for the iron meteorites. After a period as vice president for research at Lehigh, in 1993 he moved to the University of Massachusetts to serve as dean of engineering, but during these administrative appointments Joe produced a steady stream of scientific results. Joe has served as Councilor, Treasurer, Vice President, and President of the Meteoritical Society. He received the Leonard Medal in 2005, the Sorby Award in 1999, and the Dumcumb Award for in 2008.

Figure 1 Open in figure viewer PowerPoint Joseph Goldstein.     

Photographic spectrophotometry of selected bright B and Be Stars

Coudé spectra taken in the red region of 49 bright B and Be stars were examined for the behaviour of Hα and the He I λλ 5876 and 6678 line profiles. 51 per cent of the stars were found to show Hα emission to some degree and 22 per cent showed helium emission. Evidence is presented for the existence of drastic changes in the line profile and the radial velocity in some of the stars on a time scale of fractions of a day. Visiting Astronomer, Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory, operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation.     

Properties of the He I 10830 A Line in Solar Flares

We study the properties of the He I 10830 (A) line in nine selected solar flares, using spectral data obtained with the Multi-channel Infrared Solar Spectrograph (MISS) at Purple Mountain Observatory (PMO) and photospheric images from the Michelson Doppler Imager (MD1) onboard the Solar and Heliospheric Observatory (SOHO). Our results indicate that, over an area of 3"- 8", the He I 10830 (A) line shows emission exceeding the continuum in nearby quiet region when the Geostationary Operations Environmental Satellite (GOES) X-ray class of the flare reaches a threshold value (C4.5). The He I 10830A line emission is detected only in the kernels of the Hα brightenings, but is not associated with the size of the flare. It is found that, whenever the He I 10830(A) line shows excess emission over the nearby continuum both the Hα and the Ca II 8542 (A) lines display enhanced intensities exceeding their preflare intensities. The He I 10830(A) line emission can occasionally extend into the umbra of the involved sunspot, which is inconsistent with previous studies. The weak com-ponent of He I 10830(A) line changes from emission to absorption earlier than does the main component. Our results favor the photoionization-reconnection mechanism for the excitation of the He I 10830(A) line.     

Observations of the compact group of galaxies Shahbazian 130

Byurakan Astrophysical Observatory and Special Astrophysical Observatory, Academy of Sciences. Translated fromAstrofizika, Vol. 35, No. 1, pp. 67–75, July–August, 1991.     

Line variability in the spectrum of supergiant α Cam

CCD spectra taken with the PFES and CEGS echelle spectrographs attached to the 6-m Special Astrophysical Observatory (Russian Academy of Sciences) telescope and the 2-m Shamakha Astrophysical Observatory (National Academy of Sciences of Azerbaijan) telescope, respectively, were used to study the line-profile variations in the spectrum of the hot supergiant α Cam. No fast (≤1.5 h) line-profile and radial-velocity variations were found. Some of the systematic effects that cause spurious variability are considered. The Hα-profile variability appears symmetric relative to the radial velocity of the star’s center of mass and is attributable to variable blueshifted and redshifted emission and/or absorption components superimposed on a variable photospheric profile. The Hα line shows evidence of a large-scale mass ejection from the stellar surface, which is also traceable in other spectral lines. The He II 4686 line exhibits an inverse P Cyg profile, while the red wing of the He I 5876 line shows weak and variable emission. The fast (on characteristic time scales of shorter than an hour) variability of the He II 4686 profile that was previously revealed by our observations (Kholtygin et al. 2000) is called into question. A comparison of the observational data on the variability of ultraviolet and optical line profiles for the supergiant αCam suggests that nonradial motions are mainly responsible for the radial-velocity and line-profile variability.     

Las Cumbres Observatory Global Telescope: A homogeneous telescope network

Las Cumbres Observatory Global Telescope is a research organisation in the process of designing and building a network of robotic telescopes to be used for research in time‐domain astrophysics and education. The network will have complete latitude coverage in both hemispheres to allow continuous observations of any target. In other words, we will keep you in the dark. We describe the current status of our facilities and our vision for the full network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Estimation of Fried's Parameter From Specklegrams of Solar Features

A few methods of estimating Fried's parameter (r ₀) from specklegrams of solar features are described. Some of these methods were used to estimate r ₀ for the speckle data obtained from Kodaikanal Observatory (KO), Uttar Pradesh State Observatory (UPSO) and Udaipur Solar Observatory (USO). The average value of r ₀ was found to be 3 cm at USO and UPSO during our observations. At KO, values of r ₀ ranging from 6 to 10 cm were estimated.