Determination of Optical Positions for 22 Southern Extragalactic Radio Sources

2002 ◽  
Vol 123 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Z. H. Tang ◽  
S. H. Wang ◽  
W. J. Jin
Keyword(s):  
Radio Sources ◽  
Extragalactic Radio Sources

scholarly journals Optical Reference Frame Defined by Carlsberg Meridian Catalogue La Palma Number 4

1990 ◽  
Vol 141 ◽  
pp. 391-401
Author(s):  
LV Morrison ◽  
RW Argyle ◽  
L Helmer ◽  
C Fabricius ◽  
OH Einicke ◽  
...  
Keyword(s):  
Reference Frame ◽  
Proper Motion ◽  
Reference Frames ◽  
Radio Sources ◽  
Present Epoch ◽  
Extragalactic Radio Sources ◽  
La Palma ◽  
Average Accuracy ◽  
Optical Reference

The contribution of the Carlsberg Meridian Catalogue La Palma Number 4 to the determination of the optical reference frame is discussed. This catalogue of almost 51000 stars provides one of the most accurate optical reference frames at the present epoch, having a density of 1 star per square degree, and an average accuracy of 0.″12 in position and 0.″003 per year in proper motion for stars with V<9. The catalogue also contains positions of reference stars with V>11 in the fields of benchmark extragalactic radio sources which can be used in linking the optical reference frame defined by the FK5 to the extragalactic frame.

scholarly journals Determination of Optical Positions for Extragalactic Radio Sources under the Collaboration Between SHAO and NAO

2000 ◽  
Vol 180 ◽  
pp. 57-60
Author(s):  
Z.H. Tang ◽  
W.J. Jin ◽  
S.H. Wang ◽  
G. Pinigin ◽  
A. Shulga ◽  
...  
Keyword(s):  
Astronomical Observatory ◽  
Radio Sources ◽  
Meridian Circle ◽  
Extragalactic Radio Sources ◽  
Preliminary Results ◽  
Cooperative Project

AbstractThe optical positions of 9 compact extragalactic radio sources have been determined by using the 1.56m, 1m and 60/90cm telescopes with CCDs in China and the Axial Meridian Circle at Nikolaev Astronomical Observatory since Jan. 1996 in a cooperative project between the two observatories. The instrumentation, observations and reduction are briefly described, and the preliminary results are presented. The comparison between the optical and radio positions for 9 sources are also given. More optical positions of radio sources are being processed.

scholarly journals Nearly Microarcsecond Precision Differential Astrometry

1984 ◽  
Vol 110 ◽  
pp. 361-362
Author(s):  
J. Marcaide ◽  
I. Shapiro ◽  
J. Ball ◽  
N. Bartel ◽  
T. Clark ◽  
...  
Keyword(s):  
Small Angle ◽  
Radio Sources ◽  
Extragalactic Radio Sources ◽  
Propagation Medium ◽  
The Individual

In studies of extragalactic radio sources with multiple compact components the determination of which components, if any, are stationary and which moving is of importance. In order to learn about the radio properties of the individual components it is also relevant to be able to register maps made at several wavelengths. Both tasks are usually not possible with VLBI because of the irrecoverable corruption of the fringe phase introduced by the propagation medium and the instrumentation. However, when two or more compact radio sources are separated by only a small angle from each other difference techniques can be used to help tackle both questions.

The current Hamburg Program of precise optical positions of radio sources in the FK4 System

1978 ◽  
Vol 48 ◽  
pp. 113-120
Author(s):  
Chr. de Vegt ◽  
U. K. Gehlich
Keyword(s):  
Northern Hemisphere ◽  
Radio Sources ◽  
Pilot Program ◽  
Extragalactic Radio Sources ◽  
Radio Stars ◽  
Observational Program

In 1975 an observational program for the determination of precise positions of optical counterparts of extragalactic radio sources in the FK4 system has been started at the Hamburg Observatory. The sources have been selected from the recent radio lists by Elsmore and Ryle (1976), Wade and Johnston (1977) and Clark et al. (1976) to perform a comparison between the radio- and independent optical positions in the FK4 system. The results from a pilot program to be reported here partly, which includes 17 sources (de Vegt and Gehlich, 1978), encouraged us to extend the program to at present 34 extragalactic sources and 14 radio stars on the northern hemisphere; a list of these sources is given in the appendix.

scholarly journals Astrometric Programmes of the Abastumani Observatory

1995 ◽  
Vol 148 ◽  
pp. 241-244
Author(s):  
Soso M. Chanturiya ◽  
Raguli I. Inasaridze ◽  
Rolan I. Kiladze ◽  
Omar M. Kurtanidze
Keyword(s):  
Giant Planet ◽  
Radio Sources ◽  
Minor Planets ◽  
Late Type ◽  
Byurakan Survey ◽  
Extragalactic Radio Sources

AbstractAstrometric investigations undertaken with the 70 cm meniscus and 40 cm double astrograph telescopes are considered. We describe the determination of accurate positions for minor planets, giant-planet satellites, late-type stars, extragalactic radio-sources, optically discovered quasars and compact extragalactic objects in the Second Byurakan Survey.

scholarly journals On the Determination of an Astrometric Center of a Quasar

1991 ◽  
Vol 127 ◽  
pp. 261-261
Author(s):  
Roman Galas
Keyword(s):  
Numerical Calculations ◽  
Radio Sources ◽  
Extragalactic Radio Sources ◽  
Definition Of ◽  
Optical Structure

AbstractThe influence of optical structure of compact extragalactic radio sources on the definition of their centroids is discussed. Numerical calculations are performed using 4C 31.63 as an example. The results show that the presence of the underlying luminous galaxy does not lead to an unusual decrease of the accuracy in the optical astrometric measurements.

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