- ID:
- ivo://CDS.VizieR/I/171
- Title:
- Astrographic Catalog Reference Stars (ACRS)
- Short Name:
- I/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ACRS is an all-sky catalog of positions and proper motions that is based on the AGK3 in the north and on the newly completed second Cape Photographic Catalogue (CPC2, de Vegt et al. 1989) in the south. The astrometric data are on the system of the International Reference Stars (IRS, catalog <I/172>), compiled on B1950.0 FK4 and then transformed to J2000.0 FK5. The ACRS contains 320,111 stars, the mean positions for which were derived from a total of 1,643,783 individual input positions. The catalog is divided into two parts. Part 1 contains stars having better observational histories and, therefore, more reliable positions and proper motions, while the stars in Part 2 have poor histories and consist mostly of objects for which only two catalog positions in one or both coordinates were available for computing proper motions. For Part 1, which consists of 78 percent of the catalog, the mean errors of the proper motions in right ascension and declination are 0.47 and 0.46 seconds of arc/century (4.7 and 4.6 mas/yr), respectively. It is intended that, as more observations are accumulated for stars in Part 2, they will be migrated to Part 1. The catalog was compiled at the U.S. Naval Observatory, Washington, D.C., for purposes of performing new reductions of the Astrographic Catalogue plates. Additional details about the construction of the ACRS may be found in Corbin and Urban (1989). The data included are catalog part, ACRS number, equatorial coordinates (equinox, equator, epoch B1950.0 and J2000.0), proper motions (B1950.0 and J2000.0), original epochs, weights for right ascension and declination, and reference data such as DM numbers (BD, CD, CPD), AGK3 and CPC2 designations, and an IAU recommended ACRS identifier (based on coordinates).
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- ID:
- ivo://CDS.VizieR/I/96
- Title:
- Astrographic Catalogue, +01 to +31 Degrees
- Short Name:
- I/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This machine-readable version of the Astrographic Catalogue (AC), zones +01 to +31 degrees is the result of the determination of mean values for position and magnitude at a mean epoch of observation for each unique star in the original catalogs. The zones considered here (Oxford, Paris, Bordeaux, Toulouse, Algiers [partial]) contained 1,870,976 individual measures, from which the catalog of mean data for 1,025,208 stars was derived. Further analysis by Dr. D.W. Dunham and at the ADC yielded an additional 27897 apparently duplicate entries, which were eliminated to produce the final catalog. The estimated mean standard errors for positional and magnitude data are 0.4 arcsec in each coordinate and 0.4 mag, respectively. Data in this version include <m(pg)>, <Epoch>, <RA> at mean epoch, <DEC> at mean epoch. The mean values are unweighted. No star identifications are provided; hence the user must select stars from the catalog and then identify them in other catalogs or on charts using the equatorial coordinates.
- ID:
- ivo://CDS.VizieR/I/154
- Title:
- Astrographic Catalogue, Zones -02 to +31 degrees
- Short Name:
- I/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The "Astrographic Catalogue" (or "Carte de Ciel") is a catalogue of star positions and magnitudes, determined on the photographic plates taken by the normal astrographs which are installed in observatories of various latitudes, as a world-wide astronomical project (see Eichhorn, 1974, p279). The catalogue is divided into 22 declination zones, each of which is assigned to each observatory, e.g., a zone from +18 to +24 degrees is to Paris observatory. A part of this catalogue, i.e., zones from -02 to +31 degrees, was once recompiled by using AGK2/3 catalogue as the reference (Lacroute 1981), and is already archived in CDS as catalogues I/21 and 22. The present catalogue gives the result of recalculation of the same zones, by using AGK3 catalogue (printed Hamburg version) as the reference. Note that since the content of stars per plate has not been checked, there may be some entries missing. The participated observatories and the archived files are as follows: ------------------------------------------------------ declination zone observatory file ------------------------------------------------------ -02 to +04 Algiers f1 +05 to +10 Toulouse f2 +11 to +17 Bordeaux f3 +18 to +24 Paris f4 +25 to +31 Oxford I f5 ------------------------------------------------------ Note that +11 degree zone is also observed by Toulouse, and the results are included in the file f2 .
- ID:
- ivo://CDS.VizieR/J/A+AS/132/195
- Title:
- Astrolabe observations of the Sun in 1995-1997
- Short Name:
- J/A+AS/132/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the Sun with a modified Danjon astrolabe at 30{deg} and 60{deg} zenith distances have been carried out since 1990 at Santiago, Chile. Here are presented the results in right ascension, parameter Y and apparent semidiameter obtained during the period 1995-1997. These results and those obtained in for mer years are available in electronic form. The differences astrolabe minus ephemeris in {alpha} and semidiameter are briefly discussed.
- ID:
- ivo://CDS.VizieR/J/A+AS/102/11
- Title:
- Astrolabe observations of the Sun in 1990-1992
- Short Name:
- J/A+AS/102/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/375/614
- Title:
- Astrolabe observations of the Sun in 1990-2000
- Short Name:
- J/A+A/375/614
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The two tables are an update of all observations (1990-2000) of the Sun performed at Santiago, Chile, with a modified Danjon astrolabe at 30{deg} and 60{deg} zenith distances.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A17
- Title:
- Astrometrically-selected QSO candidates
- Short Name:
- J/A+A/644/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we explore the efficiency and fidelity of a purely astrometric selection of quasars as point sources with zero proper motions in the Gaia data release 2 (DR2). We have built a complete candidate sample including 104 Gaia-DR2 point sources, which are brighter than 20th magnitude in the Gaia G-band within one degree of the north Galactic pole (NGP); all of them have proper motions that are consistent with zero within 2{sigma} uncertainty. In addition to pre-existing spectra, we have secured long-slit spectroscopy of all the remaining candidates and find that all 104 stationary point sources in the field can be classified as either quasars (63) or stars (41). One of the new quasars that we discover is particularly interesting as the line-of-sight to it passes through the disc of a foreground (z=0.022) galaxy, which imprints both NaD absorption and dust extinction on the quasar spectrum. The selection efficiency of the zero-proper-motion criterion at high Galactic latitudes is thus =~60%. Based on this complete quasar sample, we examine the basic properties of the underlying quasar population within the imposed limiting magnitude. We find that the surface density of quasars is 20deg^-2^ (at G<20mag), the redshift distribution peaks at z~1.5, and only eight systems (13_-3_^+5^%) show significant dust reddening. We then explore the selection efficiency of commonly used optical, near-, and mid-infrared quasar identification techniques and find that they are all complete at the 85-90% level compared to the astrometric selection. Finally, we discuss how the astrometric selection can be improved to an efficiency of =~70% by including an additional cut requiring parallaxes of the candidates to be consistent with zero within 2{sigma}. The selection efficiency will further increase with the release of future, more sensitive astrometric measurements from the Gaia mission. This type of selection, which is purely based on the astrometry of the quasar candidates, is unbiased in terms of colours and intrinsic emission mechanisms of the quasars and thus provides the most complete census of the quasar population within the limiting magnitude of Gaia.
- ID:
- ivo://CDS.VizieR/J/A+A/565/A56
- Title:
- Astrometric asteroid masses
- Short Name:
- J/A+A/565/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using over 89 million astrometric observations of 349,737 numbered minor planets, an attempt was made to determine the masses of 230 of them by simultaneously solving for corrections to all orbital elements and the masses. For 132 minor planets an acceptable result was obtained, 49 of which appear to be new.
- ID:
- ivo://CDS.VizieR/J/A+A/565/A21
- Title:
- Astrometric catalog around ultracool dwarfs
- Short Name:
- J/A+A/565/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the astrometric reduction of images obtained with the FORS2/VLT camera in the framework of an astrometric planet search around 20 M/L-transition dwarfs. We present the correction of systematic errors, the achieved astrometric performance, and a new astrometric catalogue containing the faint reference stars in 20 fields located close to the galactic plane. Remote reference stars are used both to determine the astrometric trajectories of the nearby planet search targets and to identify and correct systematic errors. We detected three types of systematic errors in the FORS2 astrometry: the relative motion of the camera's two CCD chips, errors that are correlated in space, and an error contribution of yet unexplained origin. The relative CCD motion has probably a thermal origin and usually is 0.001-0.010px (0.1-1mas), but sometimes amounts to 0.02-0.05px (3-6mas). This instability and space- correlated errors are detected and mitigated using reference stars. The third component of unknown origin has an amplitude of 0.03-0.14mas and is independent of the observing conditions. We find that a consecutive sequence of 32 images of a well-exposed star over 40min at 0.6arcsec seeing results in a median r.m.s. of the epoch residuals of 0.126mas. Overall, the epoch residuals are distributed according to a normal law with a {chi}^2^ value near unity. We compiled a catalogue of 12000 stars with I-band magnitudes of 16-22 located in 20 fields, each covering 2x2'. It contains I-band magnitudes, ICRF positions with 40-70mas precision, and relative proper motions and absolute trigonometric parallaxes with a precision of 0.1mas/yr and 0.1mas at the bright end, respectively. This work shows that an astrometric accuracy of ~100 micro-arcseconds over two years can be achieved with a large optical telescope in a survey covering several targets and varying observing conditions.
- ID:
- ivo://CDS.VizieR/J/A+AS/93/463
- Title:
- Astrometric catalog of Southern Dwarf Novae
- Short Name:
- J/A+AS/93/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An astrometric catalog of 116 southern and equatorial dwarf novae is presented. The mean internal accuracy of the coordinates is of the order of +/- 0.025 s in alpha cos delta and +/- 0.3 arcsec in delta.
