Star catalog position and proper motion corrections in asteroid astrometry II: The Gaia era

A high density reference star catalog is being compiled at the U. S. Naval Observatory for the purpose of making new reductions of the Astrographic Catalog. The catalog will be a replacement to the SAO catalog and will be derived from the large photographic catalogs and the modern meridian circle catalogs. It is expected that the final catalog will contain 346, 000 stars, with proper motion mean errors generally or less, on a uniform system, the data having been reduced first to FK4 and then to FK5 using the International Reference Stars (IRS).

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Large-scale Motion of Solar Filaments

International Astronomical Union Colloquium ◽

10.1017/s0252921100064502 ◽

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.

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Status of “AGK4” Project

International Astronomical Union Colloquium ◽

10.1017/s0252921100074558 ◽

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.

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Status of the Lick Proper Motion Program

International Astronomical Union Colloquium ◽

10.1017/s0252921100074339 ◽

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.

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Linking the FK5 to the ICRF

Highlights of Astronomy ◽

10.1017/s1539299600020840 ◽

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.

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CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

Highlights of Astronomy ◽

10.1017/s153929960002205x ◽

1998 ◽

Vol 11 (1) ◽

pp. 551-551

Author(s):

N. Zacharias ◽

M.I. Zacharias ◽

C. de Vegt ◽

C.A. Murray

Keyword(s):

Southern Hemisphere ◽

Systematic Errors ◽

Reference Star ◽

Proper Motions ◽

Positional Accuracy ◽

Star Catalog ◽

Naval Observatory ◽

Celestial Reference System ◽

First Time ◽

Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

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Hipparcos Astrometric Results

Highlights of Astronomy ◽

10.1017/s1539299600021973 ◽

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.

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VLBI Pulsar Astrometry

Symposium - International Astronomical Union ◽

10.1017/s007418090022161x ◽

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.

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Progress Report on the Southern Proper Motion Program

Symposium - International Astronomical Union ◽

10.1017/s0074180900228404 ◽

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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