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41. Astrographic Catalogue, +01 to +31 Degrees
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.
42. Astrolabe observations of the Sun in 1995-1997
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.
43. Astrolabe observations of the Sun in 1990-1992
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)
44. Astrolabe observations of the Sun in 1990-2000
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.
45. Astrometric catalog around ultracool dwarfs
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.
46. Astrometric catalog of Southern Dwarf Novae
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.
47. Astrometric Catalogue 5, LQAC-5
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.
48. Astrometric catalogue of stars KMAC3
ID:
ivo://CDS.VizieR/I/338
Title:
Astrometric catalogue of stars KMAC3
Short Name:
I/338
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results of astrometric observations of faint V<17mag stars obtained with the Kyiv meridian axial circle. Observations were carried out in 2010-2015 in a declination zone of +2 +5.5 degrees and with use of Johnson V-band filter. The catalogue contains data for about 2 million of stars.
49. Astrometric catalogue of stars KMAC2
ID:
ivo://CDS.VizieR/I/332
Title:
Astrometric catalogue of stars KMAC2
Short Name:
I/332
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results of astrometric observations of faint V<17mag stars obtained with the Kyiv meridian axial circle. Observations were carried out in 2001-2005 in a declination zone of 0+2 degrees and with use of Johnson V-band filter. The catalogue contains data for about a million of stars.
50. Astrometric classification of 647 VLBI sources
ID:
ivo://CDS.VizieR/J/A+A/618/A80
Title:
Astrometric classification of 647 VLBI sources
Short Name:
J/A+A/618/A80
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the result of our Allan standard deviation based classification according to their astrometric stability. The classification is divided into three categories (stable sources, intermediate sources, unstable sources). Stability of sources is qualified by the astrometric behavior of the source. This determines in which category the source falls into. Then, stability of the source is also quantified by a stability index (two are proposed in the table). Those indexes enable to order sources in each category of the classification.

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