- 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 .
Number of results to display per page
Search Results
- 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://edu.gavo.org/gavo_aladincalib
- Title:
- Astrometric Calibration using Aladin
- Date:
- 03 Apr 2025 09:45:51
- Publisher:
- The GAVO DC team
- Description:
- The VO client Aladin offers powerful facilities of creating an astrometrical calibration to images lacking WCS (World Coordinate System) information. This tutorial shows how to go about doing this for an image of the Ring Nebula in Lyr.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A145
- Title:
- Astrometric Catalogue 5, LQAC-5
- Short Name:
- J/A+A/624/A145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In addition to their great astrophysical interest, quasars represent quasi-ideal reference objects in the celestial sphere with, a priori, a lack of significant proper motion. Since the fourth release of the Large Quasar Astrometric Catalogue (LQAC-4), a large number of quasars have been discovered, in particular those coming from the DR14Q release of the SDSS. With the advent of the Gaia Data Release 2 (DR2), it is now also possible to fold in extremely accurate quasar positions. Following the same procedure as in the previous releases of the LQAC, our aim is to compile the large majority of the recorded quasars, with their best estimated coordinates and substantial information about their physical properties such as the redshift, multi-bands apparent, and absolute magnitudes. Emphasis is given to the results of the cross-matches with the Gaia DR2 catalogue, which considerably increases the positional accuracy. New quasars from the SDSS DR14Q release were cross-matched with the precedent LQAC-4 compilation with a 1" search radius, which leads to 149084 objects not present in the previous LQAC-4 release. Another cross-match was done with the Gaia DR2 catalogue, which enables us to considerably improve the positioning of these objects. For the first time, parallaxes and proper motions from the DR2, when available, are added to our compilation. Furthermore, a cross-identification of the LQAC-5 with the AllWISE survey gives additional mid-infrared information for an important percentage of objects. Our final catalogue, namely the LQAC-5, contains 592 809 quasars. This represents roughly a 34% increase with respect to the number of objects recorded in the LQAC-4. Among them, 398 697 objects were found in common with the Gaia DR2, within a 1" search radius. That corresponds to 67.26% of the whole population of the compilation. The LQAC-5 delivers a nearly complete catalogue of spectroscopically confirmed quasars (including a small proportion of 14126 compact AGN's) to the astronomical community, with the aim of giving their best equatorial coordinates with respect to the ICRF2 and with exhaustive additional information. For more than 50% of the sample, these coordinates are extracted from the very recent Gaia DR2.
