scholarly journals Absolute proper motion and Galactic orbit of M92

1994 ◽  
Vol 266 (4) ◽  
pp. 925-932 ◽  
Author(s):  
R.- D. Scholz ◽  
M. Odenkirchen ◽  
M. J. Irwin
Keyword(s):  
Proper Motion ◽  
Galactic Orbit

scholarly journals The absolute proper motion and Galactic orbit of M3

1993 ◽  
Vol 264 (3) ◽  
pp. 579-586 ◽  
Author(s):  
R.- D. Scholz ◽  
M. Odenkirchen ◽  
M. J. Irwin
Keyword(s):  
Proper Motion ◽  
The Absolute ◽  
Galactic Orbit

The Local Galactic Escape Velocity

1984 ◽  
Vol 88 ◽  
pp. 187-188
Author(s):  
Bruce W. Carney ◽  
David W. Latham ◽  
Ruth C. Peterson
Keyword(s):  
Proper Motion ◽  
Rest Frame ◽  
Escape Velocity ◽  
The South ◽  
Circular Velocity ◽  
Upper Limits ◽  
Galactic Orbit ◽  
Local Value

AbstractWe discuss the corrections to the perceived motions of stars due to the disk’s circular velocity, which we determine to be 220 km sec . This implies a Keplerian escape velocity of 310 km sec−1. We discuss upper limits to the rest-frame space velocities of stars from four sources: the summary of Saio and Yoshii (1979); the large new survey of proper motion stars of Carney and Latham (1985); a study of 27 faint proper motion stars near the South Galactic Pole by Carney and Peterson (1984a); and observations by Carney and Peterson (1984b) of stars with possibly extreme velocities identified by Eggen (1969). We find the maximum velocities are near 500 km secc−1, which is likely to be the local value of the escape velocity. This implies a large amount of gravitating matter outside the solar galactic orbit.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

Status of “AGK4” Project

1978 ◽  
Vol 48 ◽  
pp. 527-533
Author(s):  
Chr. de Vegt
Keyword(s):  
Northern Hemisphere ◽  
Proper Motion ◽  
The Mean ◽  
Spectral Bandpass

The present accuracy limit for the majority of fainter stars on the northern hemisphere is set by the AGK2/3-catalogue, recently completely finished, but it should be noted that its epoch is much earlier (1960). Furtheron the AGK3-catalogue is a direct repetition of the AGK2, the plates have been taken with the same astrograph in a broad blue spectral bandpass and measured visually with the same equipment, therefore virtually an instrumental standard of 1930 is realized again. Figure 1 shows the mean errors of the AGK2/3 catalogue positions as a function of magnitude. The best accuracy for the AGK2/3 data is obtained for the stars of about ninth magnitude: 017 (AGK2) and 020 (AGK3) but decreases for the faint stars with mpg11 to 019 (AGK2) and Pg 027 (AGK3). Here the AGK3 data are even less accurate. With increasing distance to the catalogue epochs, the accuracy of positions decreases due to the proper motion errors. In the upper part of figure 2 the dependence of the AGK2/3 catalogue accuracy on time is shown for the faint stars separately and an averaged value.

Status of the Lick Proper Motion Program

1978 ◽  
Vol 48 ◽  
pp. 387-388
Author(s):  
A. R. Klemola
Keyword(s):  
Proper Motion ◽  
The Future

Second-epoch photographs have now been obtained for nearly 850 of the 1246 fields of the proper motion program with centers at declination -20° and northwards. For the sky at 0° and northward only 130 fields remain to be taken in the next year or two. The 270 southern fields with centers at -5° to -20° remain for the future.

scholarly journals Linking the FK5 to the ICRF

1998 ◽  
Vol 11 (1) ◽  
pp. 313-316
Author(s):  
F. Mignard ◽  
M. Froeschile
Keyword(s):  
Reference Frame ◽  
Proper Motion ◽  
Harmonic Functions ◽  
Optical Reference ◽  
Precessional Motion ◽  
Precession Constant

Abstract The Hipparcos optical reference frame is compared to the basic FK5 in order to determine the orientation at T0 = 1991.25 and the global spin between the two frames. The components of the spin are significant and suggest a correction the IAU76 value of the precession constant and to a possible non-precessional motion of the equinox of the FK5. The regional errors are analysed with harmonic functions and found to be as large as 150 mas in position and 3 mas/yr in proper motion.

scholarly journals Hipparcos Astrometric Results

1998 ◽  
Vol 11 (1) ◽  
pp. 536-538
Author(s):  
J. Kovalevsky
Keyword(s):  
Proper Motion ◽  
Reference System ◽  
Systematic Errors ◽  
One Dimensional

Abstract The astrometric results of Hipparcos include the positions at epoch (1991.25), the proper motion in the new IAU extragalactic reference system (ICRS), and parallaxes for about 118 000 stars. One dimensional positions are also given for 48 asteroids and 3 satellites. Due to the non-isotropy of the scanning law, the uncertainties are position dependent. Some indications of the remaining correlations are given. Various tests and comparisons show that systematic errors in parallax, if any, are not larger than 0.1 millisecond of arc.

scholarly journals VLBI Pulsar Astrometry

2001 ◽  
Vol 205 ◽  
pp. 404-407
Author(s):  
R.M. Campbell
Keyword(s):  
Proper Motion ◽  
Vlbi Observations ◽  
Recent Developments

I briefly review the means by which VLBI observations can determine the position, proper motion, and parallax of a pulsar, consider a subset of the applications of such results, and highlight recent developments in pulsar gating at JIVE.

scholarly journals Progress Report on the Southern Proper Motion Program

1995 ◽  
Vol 166 ◽  
pp. 357-357
Author(s):  
I. Platais ◽  
T. M. Girard ◽  
V. Kozhurina-Platais ◽  
R. A. Mendez ◽  
W. F. Van Altena ◽  
...  
Keyword(s):  
Reference Frame ◽  
Proper Motion ◽  
Systematic Errors ◽  
Progress Report ◽  
Model Choice ◽  
Plate Model ◽  
Field Independent ◽  
The Status ◽  
First Results ◽  
Galaxy Model

We present the status of the Yale/San Juan Southern Proper Motion program (SPM) which is the southern hemisphere extension of the Lick Observatory Northern Proper Motion program with respect to faint galaxies (Platais et al., 1993). To date, measurements and reductions in the South Galactic Pole region comprising ≈ 1000 square-degrees on the sky have been finished. At this stage of the SPM program particular attention has been paid to the plate model choice along with an assessment of and accounting for systematic errors. For our establishing of a secondary reference frame we have noticed the presence of a potentially dangerous effect, so–called field–independent coma which is caused by lens decentering. We acknowledge the superb Hipparcos preliminary positions without which such analysis would be virtually impossible. The SPM data at the SGP region have also been used to constrain a multi–component Galaxy model. First results of this analysis are presented.

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