We present 18365 astrometric observations of 290 visual binaries obtained with the 26-inch refractor of Pulkovo Observatory during 2014-2019. The separation between components is from 1.3" to 37" with a median value of 4.8". For a single observation, the mean separation error is 0.013", and the mean position angle error is 0.44{deg}/rho, where rho is an angular distance in arcseconds. We compare the observations of sample stars with the data from the Gaia DR2 catalog and the results of the ground-based observations performed with other telescopes.
We present the results of 3632 astrometric CCD-measurements of 314 visual double stars performed with the 26-inch refractor of the Pulkovo observatory in 2003-2007. Angular separations (rho) and position angles (theta) are provided. Mean values of standard errors are 0.009" in rho and 0.40(deg)/rho in theta, where rho is the separation in arcseconds.
CCD positions for eight Jovian irregular satellites
Short Name:
J/A+A/453/349
Date:
21 Oct 2021
Publisher:
CDS
Description:
The astrometric positions of eight irregular Jovian satellites are given for the oppositions of the planet from 1995 to 1999. These positions were measured on 204 CCD frames obtained at the Cassegrain focus of a 1.6m reflector. They are compared with the theoretically calculated positions from JPL Development Ephemeris. The observed minus-calculated standard deviation for all observations of the eight satellites are {sigma}_RA_=0.071" and {sigma}_DE_=0.052". The USNO-A2.0 (<I/252>) catalog was used for the astrometric calibration.
Astrometric observations of Triton are given for the oppositions of Neptune on 1995, 1996 and two nights of 1997. In this period, 759 frames were obtained during 35 nights at the Cassegrain focus of the 1.6m and the 0.6m reflectors of the LNA-Brazil. The comparison with calculated positions gives residuals with standard deviation of the order of 0.09".
Continuing a CCD survey of galaxies belonging or projected onto the Coma and Hercules Superclusters, to the A262 and Cancer clusters, we present isophote maps and photometric profiles in the Johnson system of 111 galaxies (67 in the V and B bands, 42 only in V, 2 only in B) obtained with the 2.1m telescope at San Pedro Martir (Baja California, Mexico).
We present the CdC2000 catalogue issued from the reduction of the complete Bordeaux Carte du Ciel zone observed at the beginning of last century with the Bordeaux astrograph. This catalogue is a positional catalogue of 344780 stars covering the declination zone +11{deg}<delta<+18{deg}. The average epoch of positions is 1914.7. The data are from the 512 Carte du Ciel plates archived at the Bordeaux Observatory and scanned with the APM Cambridge automatic measuring machine. Plates have been individually reduced using the TYCHO-2 Catalogue as astrometric reference. Astrometric standard errors are about 0.10" to 0.12" on positions and 0.6 magnitudes on photographic magnitudes. A detailed study of errors and a comparison of various reduction methods are presented in order to take into account the significant propagated errors from the reference catalogue. The CdC2000 provides positions at the epoch of the plates for 50 682 TYCHO-2 stars. The associated positions are proved to be 0.11" more precise than the positions given by the Tycho-2 catalogue at the epoch of the plates. This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone (PM2000, Cat. <I/300>).
We present astrometric results for compact extragalactic objects observed with the Very Long Baseline Array at radio frequencies of 24 and 43GHz. Data were obtained from ten 24-hr observing sessions made over a five-year period. These observations were motivated by the need to extend the International Celestial Reference Frame (ICRF) to higher radio frequencies to enable improved deep space navigation after 2016 and to improve state-of-the-art astrometry. Source coordinates for 268 sources were estimated at 24GHz and for 131 sources at 43GHz.
We have measured the submilliarcsecond structure of 274 extragalactic sources at 24 and 43 GHz in order to assess their astrometric suitability for use in a high-frequency celestial reference frame (CRF). Ten sessions of observations with the Very Long Baseline Array have been conducted over the course of ~5 years, with a total of 1339 images produced for the 274 sources. There are several quantities that can be used to characterize the impact of intrinsic source structure on astrometric observations including the source flux density, the flux density variability, the source structure index, the source compactness, and the compactness variability.
