... The overall globular cluster population is divided by gap in the metallicity function at [Fe/H]=-1.0 into two discrete groups with well-defined maxima at [Fe/H]=-1.60?0.03 dex, and -0.60?0.04 dex. ... Clusters with extremely blue horizontal branches occupy a spherical volume of radius ~ 9 kpc, have high rotational velocities ( V rot =77?33 km/s), have substantial and equal negative radial and vertical metallicity gradients, and are, on average, the oldest group (the old-halo subsystem). ...

... Structure of Data . ... Catalog . ... In SAI OCL Catalog, we introduce our work on investigation of the Milky Way system of open star clusters. The main goal of our study is a search for new clusters using huge surveys. 168 new clusters have been already discovered by us using J,H,Ks data from 2MASS point source catalog. ... For 141 new clusters, we found their physical parameters using J,H,Ks data from 2MASS catalog and, for a number of clusters, our UBVRI CCD observational magnitudes. ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

... Commission 37: Star Clusters and Associations . Home Page . Commission 37 of the International Astronomical Union deals with all aspects of Globular Cluster, Open Cluster, and Stellar Associations research. With Commission 33 it forms Division VII of the IAU. Commission Structure . ... IAU Home Page . Open Clusters Database (maintained by J.-C. Mermilliod ) . Catalogue of Milky Way Globular Cluster Parameters (maintained by W. E. Harris ) . ...

... ACQ-DIST Optional Parameter for FGS 1 , 2 . ACQTYPE Optional Parameter for STIS . Acquisition modes . ... Aperture Coordinate System . ... AFTER date Special Requirement . ... BINAXIS1, BINAXIS2 Optional Parameters for STIS 1 , 2 . ... BUFFER-TIME Optional Parameter for STIS . ... CHECKBOX Optional Parameter for STIS . ... Calibration Targets . ... CR-SPLIT Optional Parameter for STIS . ... DIFFUSE-CENTER Optional Parameter for STIS . ... GAIN Optional Parameter for STIS . ... Position . ...

... File name for the fits binary table containing X-ray source positions and their errors. opticalset . ... File name for the fits binary table containing optical source positions and their errors. findrotation . ... boolean . ... name of B magnitude column . ... column name of optical catalogue position RA . ... column name of optical catalogue position DEC . ... column name of optical catalogue position error . ... column name of X-ray source position RA . ... column name of X-ray source position DEC...

tranback -- Transform an X,Y position from output to input pixel position using the same conventions as drizzle tranback xout yout . xout = 400 [real] . ... The X dimension of the input image (this is used to determine the centre which is the origin of the transformations). (nyin = 800) [real] . ... If "output" the input image center is mapped to the center of the output grid, rotated about that center and then shifted along the grid of the output image. ...

... Observatory . ... The Laboratory of Astrometry . Dept. for Physics of Stars&Galaxies . ... Astronomical Calendar . ... UkrVO . ... The purpose of research: Creating a stellar catalog to study the structure and kinematics of star systems, including open star clusters and stars with large proper motions; the enhancement ICRF / Hipparcos system to stars dawn to 17 m (V); Search of binary systems of brown dwarfs and determination of their parameters; astrometry of minor bodies of the Solar System. ...

... The most powerful and widely used methods to calculate the scattering matrix of a fractal cluster are based on the coupled dipoles methods (e.g. the Discrete Dipole Approximation, DDA) and the theory of light scattering by a cluster of spherical particles [2-4]. ... At present the procedure of calculation of the scattering matrix is well developed for both an oriented cluster of spherical particles and for chaotically oriented clusters of such particles [4]. ...

... We now describe the input parameters to the self-calibration tasks. ... For selfcal , you need not perform source , dra , or ddec selection if you use the selradec option (see below). minants : The minimum number of antenna that must be present before the tasks will attempt to find a solution. ... and phase : This determines whether the self-calibration tasks solve for just phase ( options=phase , which is the default) or amplitude and phase solution ( options=amplitude ). mfs : . ...

... We address a question if globular clusters (GC) in a protogalaxy could for some time evolve chemically as isolated systems, enriching themselves with heavy elements produced in first supernova events that follow initial star formation. We determine both the critical mass of a protoglobular cluster that is needed to retain the ejecta of the very first supernova, and the critical energy (i.e., number of supernovae) that is needed to expel the residual gas from a cluster of a given mass. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Top panel: comparison between the observed H and H line profile (black solid line) and synthetic profiles calculated with the final adopted parameters (dash-dotted green line) and with the parameters which were found to best fit the hydrogen line profiles (dashed red line). ... We provide photometric and spectroscopic evidence showing the star is most likely a member of the young Stock 16 open cluster (age 3тАУ8 Myr). ...

... WMAP7 -- 7 year WMAP data ( Larson at al., ... SPT -- CMB power spectrum from SPT ( Keisler et al., ... CDM -- flat Universe with cosmological constant . ... N eff 3.046 . ... WCDM -- flat Universe with dark energy . ... CDM, WMAP7+BAO+H0 +CL . CDM, WMAP7+BAO+H0+SPT +CL . ... CDM+f (1), WMAP7+SPT+BAO+H0 +CL . CDM+f (1)+N eff , WMAP7+SPT+BAO+H0 +CL . ... CDM+N eff , WMAP7+BAO+H0 +CL . ... CDM+dn/dlnk, WMAP7+BAO+H0 +CL . ... WCDM, WMAP7+SPT+BAO+H0 +CL . ... WCDM, WMAP7+SPT+BAO+H0+SNSYS +CL . ...

The problem of solar wind data correlation for the observations onboard several spacecraft is very important for three points of view: . ... This problem is studied now in detail by systematic determination of ion flux and ion velocity data correlations by INTERBALL-1 (IKI group), WIND and IMP 8 (both - MIT group). ... Solar wind plasma correlation lengths from IMP 8, WIND and INTERBALL-1. ... Correlation of solar wind observations onboard several spacecraft: INTERBALL-1, IMP 8 and WIND data. ...

... The HST uses an onboard model of its orbit to perform in real-time various control functions relating to spacecraft operations and observation support. ... New coefficients for the ephemeris are updated every other day, and are archived as FITS keywords for each HST observation data set. Using these coefficients,an observer can perform a variety of calibration and characterization calculations relating to the orbital position and velocity of the telescope. ...

... Impact of Covariance Information on the Orientation Parameters Between Radio Source Position Catalogs, IVS 2012 General Meeting Proceedings, p.339­341 http://ivscc.gsfc.nasa.gov/publications/gm2012/sokolova.pdf Impact of Covariance Information on the Orientation Parameters Between Radio Source ... IVS Analysis Centers provide these catalogs in a standard IERS format, where together with radio source positions and other relevant information, RA/DE correlations are reported. ...

The new view on the population of Galactic open clusters A.E.Piskunov1, N.V.Kharchenko2, S.RЖser3, E.Schilbach3, R.-D.Scholz4 1 2 3 4 Institute of Astronomy, Moscow, Russia Main Astronomical ... Observatory, Kiev, Ukraine Astronomisches Rechen-Institut, Heidelberg, Germany Astrophysikalisches Institut Potsdam, Germany What are open clusters and what do they teach us Groups of Population I ... Cluster complexes: OCC-1 = Gould's Belt cluster complex? ...

Topics covered by the IAU Symp. ... Do all galaxies have stellar halos? ... Stellar tracers of the MW halo and nearby galaxies; the stellar population of star clusters and their contribution to the galaxy halos . ... NEW: Scientific program of the IAU Symposium 317 can be downloaded here . ... GLOBAL PROPERTIES OF STELLAR HALOS FROM THE MILKY WAY TO EXTERNAL GALAXIES . ... DISCRETE CONSTITUENTS OF STELLAR HALOS IN THE MILKY WAY AND IN EXTERNAL GALAXIES : PLANETARY NEBULAE and GLOBULAR CLUSTERS . ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...