Proper Motions of OB Stars in Both Hemispheres

Symposium - International Astronomical Union ◽

10.1017/s0074180900069862 ◽

1974 ◽

Vol 61 ◽

pp. 227-227

Author(s):

Haruo Yasuda

Keyword(s):

Southern Hemisphere ◽

Fundamental System ◽

Systematic Errors ◽

Radial Velocities ◽

Distance Scale ◽

Proper Motions ◽

Stellar Kinematics ◽

Ob Stars

From a comparison between the rotational velocities derived from radial velocities and space motions of OB stars, large systematic errors of FK4 proper motions in the southern hemisphere are evaluated; these may be expected, from the known accuracy of the FK4. The error of adopted distance scale is also examined. It is suggested that meridian observations of OB stars should be extended to the southern hemisphere to further researches, not only on stellar kinematics, but also on the fundamental system.

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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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A Determination of Secular Parallaxes of Reference Stars from Relative Proper Motions of Open Clusters

International Astronomical Union Colloquium ◽

10.1017/s0252921100027949 ◽

1970 ◽

Vol 7 ◽

pp. 74-76

Author(s):

A. N. Deutsch

Keyword(s):

Systematic Errors ◽

Open Clusters ◽

Radial Velocities ◽

Proper Motions ◽

The Mean

The determination of secular parallaxes of stars is usually based on meridian observations of proper motions of bright stars, this introducing known systematic errors. The mean parallaxes of stars can be obtained by means of radial velocities which are known for the bright stars. The more perspective method, the reference of stars to galaxies, is not applicable at low galactic latitudes.

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Desiderata for Fk5

Highlights of Astronomy ◽

10.1017/s1539299600001325 ◽

1968 ◽

Vol 1 ◽

pp. 301-305 ◽

Cited By ~ 1

Author(s):

W. Fricke ◽

W. Gliese

Keyword(s):

Celestial Mechanics ◽

Reference System ◽

Inertial Frame ◽

Large Range ◽

Fundamental System ◽

Systematic Errors ◽

Frame Of Reference ◽

Proper Motions ◽

Astronomical Research ◽

Positional Astronomy

A fundamental catalogue compiled from independent and differential observations of stellar positions at various epochs provides the fundamental system of positions and proper motions of the stars. The system ought to be compiled in such a way that it represents the inertial frame of reference as accurately as practicable. Its direct purpose is to serve as the reference system of positional astronomy. It should fulfil the requirements of astronomical research, in particular in celestial mechanics and galactic research, as well as the demands of the astronomical determinations of time and of latitudes. It has also to fulfil the requirements of geodesy and navigation. For all these purposes the system must be uniform over the whole sky (free from regional systematic errors), and it has to be uniform over a large range of stellar magnitudes (free from errors depending on the magnitude of the stars).

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Computation of Compilation Catalogs

Symposium - International Astronomical Union ◽

10.1017/s0074180900076427 ◽

1986 ◽

Vol 109 ◽

pp. 75-86

Author(s):

Thomas E. Corbin

Keyword(s):

Southern Hemisphere ◽

Northern Hemisphere ◽

Fundamental System ◽

Proper Motions ◽

The South ◽

International Reference ◽

The North ◽

Naval Observatory ◽

Made In

Currently the computation of mean positions and proper motions for the International Reference Stars (IRS) is hampered by large variations in the observational histories of the stars and lack of overlap between the magnitudes of the IRS and of the FK4. The poorest IRS observational histories are +60° to +80° in the north and −40° to −80° in the south. The much-needed extension of the fundamental system to the ninth magnitude will be made in the FK5. The Faint Fundamental Extension is currently being selected at the U. S. Naval Observatory. A proposed list of 1030 Faint Fundamental stars has been prepared for the Northern Hemisphere, and work has begun on the selection in the Southern Hemisphere.

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Galactic Rotation Derived from OB Stars Using Hipparcos Proper Motions and Radial Velocities

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/52.1.143 ◽

2000 ◽

Vol 52 (1) ◽

pp. 143-151 ◽

Cited By ~ 17

Author(s):

Makoto Uemura ◽

Hiroyuki Ohashi ◽

Tomonori Hayakawa ◽

Eiji Ishida ◽

Taichi Kato ◽

...

Keyword(s):

Radial Velocities ◽

Galactic Rotation ◽

Proper Motions ◽

Ob Stars

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Fundamental Catalogues

Symposium - International Astronomical Union ◽

10.1017/s0074180900139464 ◽

1988 ◽

Vol 133 ◽

pp. 95-102

Author(s):

W. Gliese

Keyword(s):

Polar Motion ◽

Fundamental System ◽

Systematic Errors ◽

Proper Motions ◽

Experienced Observer ◽

Single Night

The first plates for the great enterprise, the Carte du Ciel or the Astrographic Catalogue, were taken in 1891. At that time no fundamental system existed which was usable as a basis for reference stars over the whole sky and was commonly accepted by the astronomical community. Therefore reference stars were taken from available catalogues, sometimes updated to the epoch of the plates by application of proper motions. Other observatories used their own reference stars specially observed on transit circles. For the last-mentioned method the work at the Cape Observatory is an instructive example which was described by Sir David Gill, an experienced observer, in a catalogue of Astrographic Standard Stars (Gill, 1906). The methods of observation are fully described in the volumes of the Cape Meridian Observations. For the derivation of proper motions southern catalogues dating from 1835 to 1900 were used, applying Newcomb's values for precession. The determination and elimination of serious systematic errors played an important role. “Eye-and-Ear” observers had their personal errors which even changed with the years for the same person, occasionally even during tiresome long watches in a single night. Further sources of errors include: None-reversible instruments, zenith discontinuities, magnitude equations, possible changes of flexure, pivot errors and their variations, and unsufficient knowledge of the polar motion in old catalogues. Many of these questions were investigated and described in extended introductions to observational catalogues but in some cases such problems were only incompletely explained. Reference stars for the Astrographic Catalogues were observed on various “fundamental system” if fundamental at all.

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The Contribution Of The Danjon Astrolabe To The Improvement Of The Fundamental Reference System at The Southern Hemisphere

Symposium - International Astronomical Union ◽

10.1017/s0074180900139828 ◽

1988 ◽

Vol 133 ◽

pp. 359-367

Author(s):

F. Noël

Keyword(s):

Southern Hemisphere ◽

Reference System ◽

Fundamental System ◽

Systematic Errors ◽

Historic Review ◽

Fundamental Reference

An historic review is made of the observation programs with Danjon astrolabes which were carried out or are in progress at the southern hemisphere. The consistency of their results in the research of systematic errors of the FK4 Fundamental System, largely confirmed by other observation techniques, is shown. The Cape and Santiago astrolabe catalogues, the largest ones derived so far for southern stars, are briefly reviewed.

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24. Commission des Parallaxes Stellaires et des Mouvements Propres

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00017260 ◽

1936 ◽

Vol 5 ◽

pp. 144-155

Author(s):

M. S. A. Mitchell ◽

MM. Adams ◽

Alden ◽

Bianchi ◽

Cecchini ◽

...

Keyword(s):

Southern Hemisphere ◽

Systematic Errors ◽

Probable Error ◽

Proper Motions ◽

Astrophysical Journal ◽

Trigonometric Parallaxes ◽

Substantial Progress

In November 1934 the President circulated a letter to the members of the Commission as follows:Since the 1932 meeting the following projects have been completed, or are nearing completion:(1)The publication of many lists of trigonometric parallaxes.(2)The determination of the spectroscopic parallaxes of 4179 stars at Mt Wilson Observatory by Adams, Joy and Humason.(3)A discussion of systematic errors of trigonometric parallaxes by van Maanen and a re-discussion in the Astrophysical Journal of the same material by Mitchell and by Sterne.(4)The compilation of a second Yale Catalogue to include parallaxes completed before the end of 1934.(5)Substantial progress on the proper motions of 32,000 stars by Boss and his associates at the Dudley Observatory.(6)The publication at the Radcliffe Observatory of the proper motions of 32,000 stars from photographs on 115 Selected Areas.(7)The completion of the dynamical parallaxes of 2000 stars.(8)The completion of the proper motions of 18,000 stars derived from parallax plates at the Leander McCormick Observatory.(9)The publication at the Yale Observatory of the proper motions of 40,000 stars with a probable error less than 0”.010 determined from photographs by re-observing in zones the Astronomische Gesellschaft stars.(10)The determination of the proper motions of 50,000 stars in the Southern Hemisphere by Luyten from Harvard photographs.

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