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41. 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.
42. 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.
43. Astrometric observations of Deimos
ID:
ivo://CDS.VizieR/J/A+A/545/A144
Title:
Astrometric observations of Deimos
Short Name:
J/A+A/545/A144
Date:
21 Oct 2021
Publisher:
CDS
Description:
Between July 2005 and July 2011 Mars Express performed 50 Deimos approaches. 156 SRC images were acquired and used for astrometric (positional) measurements of the small Martian satellite. For this study, we have developed a new technique, where the center-of-figure of the odd-shaped Deimos was determined by fitting the predicted to the observed satellite limb. The prediction of the limb was made based on the moon's known shape model. The camera pointing was verified and corrected by means of background star observations. We obtained a set of spacecraft- centered Deimos coordinates with accuracies between 0.6 and 3.6km (1 sigma). Comparisons with current orbit models indicate that Deimos is ahead or falling behind its predicted position along its track by as much as +3.7km or -4.4km, respectively, depending on the chosen model. Our data may be used to improve the orbit models of the satellite.
44. Astrometric observations of Phobos
ID:
ivo://CDS.VizieR/J/A+A/580/A28
Title:
Astrometric observations of Phobos
Short Name:
J/A+A/580/A28
Date:
21 Oct 2021
Publisher:
CDS
Description:
Mars Express (MEX) carried out 74 Phobos flybys at distances between 669 and 5579km from April 2008 to August 2011. Images taken with the Super Resolution Channel (SRC) were used to determine the Martian moon's spacecraft-centered right ascension and declination. Image positions of Phobos were measured using the control point and limb fit measurement techniques. Camera pointing and pointing drift were controlled by means of background star observations that were compared to the corresponding positions from the Tycho-2 catalog. Blurred and noisy images were restored by applying an image-based point spread function in a Richardson-Lucy deconvolution. Altogether, we provide 158 astrometric observations of Phobos with estimated uncertainties between 0.224 and 3.405km circular about the direction to the satellite. Control point measurements yield more accurate results than limb fit observations.
45. Astrometric observations of radio stars
ID:
ivo://CDS.VizieR/J/other/PBeiO/32.87
Title:
Astrometric observations of radio stars
Short Name:
J/other/PBeiO/32
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the data observed in San Juan with the photoelectric Astrolabe Mark II of the Beijing Astronomical Observatory from February, 1992 through March, 1997, the radio stars catalogue in San Juan (RSSJ95) has been compiled. There are 69 radio stars in this catalogue. The Positions of the radio stars are for the epoch of observation and the equinox J2000.0 and a system close that of the system FK5. The mean precisions are +/-2.2ms and +/-0.035" in right ascensions and declinations, respectively. The magnitudes of stars are from 0.9 to 10.7. The declinations are from -2.5{deg} to -60{deg}. The mean epoch is 1995.1. Finally, the comparison results with Hipparcos catalogue and CAMC are given.
46. Astrometric obs. of Phobos and Deimos in 1971
ID:
ivo://CDS.VizieR/J/A+A/572/A104
Title:
Astrometric obs. of Phobos and Deimos in 1971
Short Name:
J/A+A/572/A104
Date:
21 Oct 2021
Publisher:
CDS
Description:
Accurate positional measurements of planets and satellites are used to improve our knowledge of their dynamics and to infer the accuracy of planet and satellite ephemerides. In the framework of the FP7 ESPaCE project, we provide positions of Mars, Phobos and Deimos taken with the U.S. Naval Observatory 26-inch refractor during the 1971 opposition of the planet. These plates were measured with the digitizer of the Royal Observatory of Belgium and reduced through an optimal process that includes image, instrumental and spherical corrections to provide the most accurate data.
47. Astrometric positions for (84922) 2003 VS2
ID:
ivo://CDS.VizieR/J/AJ/158/159
Title:
Astrometric positions for (84922) 2003 VS2
Short Name:
J/AJ/158/159
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the plutino object (84922) 2003 VS_2_. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on 2014 November 7, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141+/-0.009 mag. This allows us to reconstruct the 3D shape of the body, with principal semi-axes of a=313.8+/-7.1 km, b=265.5_-9.8_^+8.8^ km, and c=247.3_-43.6_^+26.6^ km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of 548.3_-44.6_^+29.5^ km is about 5% larger than the radiometric diameter of 2003 VS_2_ derived from Herschel data of 523+/-35 km, but still compatible with it within error bars. From those results we can also derive the geometric albedo (0.123_-0.014_^+0.015^) and, under the assumption that the object is a Maclaurin spheroid, the density {rho}=1400_-300_^+1000^ for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g., rings or satellite) around the main body.
48. 2292 astrometric positions of asteroids
ID:
ivo://CDS.VizieR/J/other/KFNT/34.270
Title:
2292 astrometric positions of asteroids
Short Name:
J/other/KFNT/34.
Date:
22 Feb 2022
Publisher:
CDS
Description:
A catalogue of equatorial coordinates and magnitudes for 2162 asteroids and 11 comets was compiled based on the results of processing of digitized photographic observations of the northern sky performed in 1981-1985. The positions were compared with the JPL DE431 ephemeris. The mean (O-C)_RA,DE_ values for all positions obtained in this comparison are -0.08" and 0.04", and their root-mean-square errors are 0.70" and 0.64" in {alpha} and {delta}, respectively. It was found that the observations of 54 asteroids predate their discoveries, and the observations of four of them are the earliest known for these asteroids.
49. Astrometric positions of radio sources
ID:
ivo://CDS.VizieR/J/A+A/510/A10
Title:
Astrometric positions of radio sources
Short Name:
J/A+A/510/A10
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss the results of an investigation of astrometric positions of extragalactic radio sources from a list for the International Celestial Reference Frame.
50. Astrometry around RX J0720.4-3125
ID:
ivo://CDS.VizieR/J/ApJ/660/1428
Title:
Astrometry around RX J0720.4-3125
Short Name:
J/ApJ/660/1428
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used a set of dedicated astrometric data from the Hubble Space Telescope to measure the parallax and proper motion of the nearby neutron star RX J0720.4-3125. At each of eight epochs over 2 years, we used the High Resolution Camera of the Advanced Camera for Surveys to measure the position of the B=26.6 target to a precision of ~2mas (~0.07pix) relative to 22 other stars. From these data we measure a parallax of plx=2.8+/-0.9mas (for a distance of 360^+170^_-90_pc) and a proper motion of mu=107.8+/-1.2mas/yr. Exhaustive testing of every stage of our analysis suggests that it is robust, with a maximum systematic uncertainty on the parallax of 0.4mas. The distance is compatible with earlier estimates made from scaling the optical emission of RX J0720.4-3125 relative to the even closer neutron star RX J1856.5-3754. The distance and proper motion imply a transverse velocity of 180^+90^_-40_km/s, comparable to velocities observed for radio pulsars. The speed and direction suggest an origin for RX J0720.4-3125 in the Trumpler 10 OB association ~0.7Myr ago, with a possible range of 0.5-1.0Myr given by the uncertainty in the distance.

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