Astrometry with Schmidt Telescopes for Probing the Galaxy

Author(s):

C. Andrew Murray

Keyword(s):

Proper Motion ◽

Proper Motions ◽

The South ◽

Large Numbers ◽

The Galaxy ◽

Zero Points

AbstractThe use of proper motions and parallaxes for large numbers of stars, obtainable from a combination of Schmidt telescopes and automatic plate scanners, is discussed. The importance of deriving the zero points of both absolute proper motion, and of parallactic motion, is emphasised. Calibrations of proper motion and of parallaxes should be based on dispersions of proper motion. These methods are illustrated by results from a study in the South Galactic Cap.

Kinematics of Galactic Globular Clusters from Schmidt-Plate Astrometry

10.1017/s0074180900109222 ◽

1995 ◽

Vol 164 ◽

pp. 405-405 ◽

Author(s):

R.-D. Scholz ◽

S. Hirte ◽

M.J. Irwin ◽

M. Odenkirchen

Keyword(s):

Radial Velocity ◽

Proper Motion ◽

Globular Clusters ◽

Proper Motions ◽

Large Numbers ◽

Solar Motion ◽

The Galaxy ◽

Ursa Minor ◽

Galactic Globular Clusters

From measurements of Tautenburg Schmidt plates with the APM facility in Cambridge we obtained absolute proper motions of the Galactic globular clusters M 3 and M 92 directly with respect to large numbers of background galaxies (Scholz et al. 1993, 1994). We have extended our work to the dSphs in Draco and Ursa Minor (Scholz & Irwin 1994) and to other Galactic globular clusters using Tautenburg, Palomar and UK Schmidt plates. Combining our absolute proper motion of a cluster with its known radial velocity and distance (using common parameters of the solar motion) we derive the cluster orbit in the Galaxy (cf. Odenkirchen & Brosche 1992).

Proper Motions Referred to Faint Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600006262 ◽

1986 ◽

Vol 7 ◽

pp. 89-92

Author(s):

W. F. van Altena ◽

T. Girard ◽

C. E. López ◽

A. R. Klemola ◽

B. F. Jones ◽

...

Keyword(s):

Proper Motion ◽

Reference Frames ◽

Photographic Plate ◽

Proper Motions ◽

Plate Material ◽

Present Epoch ◽

Magnitude Range ◽

Large Numbers ◽

Material Forming ◽

Partial Extension

The Lick Northern Proper Motion (NPM) and the Yale-San Juan Southern Proper Motion (SPM) programs have been described on several occasions (Wright 1950; Deutsch and Klemola 1974; Vasilevskis 1973; and Wesselink 1974). The two programs represent an attempt to measure the coordinates and proper motions, with respect to the extragalactic reference frames, for large numbers of stars representing most of the astrophysically-recognized classes. The photographic plate material forming the basis of the NPM program derives from the first (1947-1954) and second (1970-present) epoch phases for 1246 fields with the Lick 51 cm Carnegie double-astrograph for centers at -20° and northward (Shane and Wirtanen 1967). A southern supplement of 144 additional fields takes the program to -30°. The SPM consists of 632 fields with centers at -20° and southward. The first epoch plates were taken between 1965 and 1974 and a partial extension of 72 fields to more northerly declinations is essentially complete. One short and one long exposure permit the measurement of positions and approximate photometry for selected stars and reference galaxies over the blue magnitude range from about 8 to 17-18.

Correction to Absolute Proper Motion Using the IAS-Galaxy Model

10.1017/s0074180900087192 ◽

1990 ◽

Vol 141 ◽

pp. 427-429

Author(s):

Kavan U. Ratnatunga

Keyword(s):

Reference Frame ◽

Proper Motion ◽

Theoretical Models ◽

Galactic Structure ◽

Coordinate Frame ◽

Proper Motions ◽

Software Interface ◽

The Galaxy ◽

Galaxy Model ◽

Star Catalogs

The IAS-Galaxy model (Ratnatunga, Bahcall and Casertano 1989) is a software interface between theoretical models of the Galaxy and observed kinematic distributions. It has been developed for analysis of many kinematic catalogs to study global galactic structure. In addition, the IASG model can be used to estimate corrections needed to derive absolute parallax and absolute proper motion by evaluating, on a star-by-star basis, the expected mean motion of the reference stars.A theoretical Galaxy model is defined on an inertial coordinate frame. Proper motions are measured in a reference frame defined by a fundamental catalog. The observed distribution of proper motions in star catalogs can be directly compared with the expected distributions evaluated using IASG to check the accuracy of the adopted reference frame in realizing the inertial coordinate frame in the sky.

Around Gaia Alerts in 20 questions

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312001305 ◽

2011 ◽

Vol 7 (S285) ◽

pp. 425-428 ◽

Author(s):

Łukasz Wyrzykowski ◽

Simon Hodgkin

Keyword(s):

Data Stream ◽

European Space Agency ◽

Space Mission ◽

Proper Motions ◽

Space Agency ◽

Large Numbers ◽

Formation History ◽

The Galaxy ◽

Optical Wavelengths ◽

Astrometric Data

AbstractGaia is a European Space Agency (ESA) astrometry space mission, and a successor to the ESA Hipparcos mission. Gaia's main goal is to collect high-precision astrometric data (positions, parallaxes, and proper motions) for the 1 billion brightest objects in the sky. Those data, complemented with multi-band, multi-epoch photometric and spectroscopic data observed from the same observing platform, will allow astronomers to reconstruct the formation history, structure, and evolution of the Galaxy.Gaia will observe the whole sky for 5 years, providing a unique opportunity for the discovery of large numbers of transient and anomalous events such as supernovæ, novæ and microlensing events, GRB afterglows, fallback supernovæ, and other theoretical or unexpected phenomena. The Photometric Science Alerts team has been tasked with the early detection, classification and prompt release of anomalous sources in the Gaia data stream. In this paper we discuss the challenges we face in preparing to use Gaia to search for transient pheonomena at optical wavelengths.

Report on the Herstmonceux I.N.T. Parallax Programme

10.1017/s0074180900069734 ◽

1974 ◽

Vol 61 ◽

pp. 167-167

Author(s):

B. F. Jones

Keyword(s):

Proper Motion ◽

Reduction Technique ◽

Royal Greenwich Observatory ◽

Proper Motions ◽

Isaac Newton ◽

The Galaxy ◽

Visual Magnitude ◽

Isaac Newton Telescope

In 1971 a pilot parallax programme was initiated on the 98-in. Isaac Newton Telescope at the Royal Greenwich Observatory. Nineteen stars between visual magnitude 15 and 19 and of high proper motion were put on the programme. The plates were taken at prime focus through the Wynne corrector. Observations are now complete for two of these stars. Because of time allocations and the desire to observe at maximum parallax factor, observations are made at large hour angles. All stars in each field are being measured on the GALAXY measuring engine and parallaxes and proper motions will be computed for all stars. The fields are being reduced using an overlap reduction technique.

Measurement of the absolute proper motions of the Magellanic Clouds

10.1017/s0074180900201277 ◽

1991 ◽

Vol 148 ◽

pp. 491-492 ◽

Author(s):

H.-J. Tucholke ◽

M. Hiesgen

Keyword(s):

Proper Motion ◽

Independent Study ◽

Magellanic Clouds ◽

Proper Motions ◽

Schmidt Telescope ◽

Large Numbers ◽

The Absolute

Currently, we are measuring the absolute proper motions of the Magellanic Clouds relative to background galaxies, using plates taken with the ESO Schmidt Telescope. In spite of the small epoch difference of about 15 years, an accuracy of 0.5-1.0 milliarcsecs (mas) may be achieved using large numbers of stars and galaxies. Measurement and reduction procedures are presented; a preliminary solution for the absolute proper motion of the LMC from the measurements of three plates gives a result similar to the independent study of Jones et al. (1989).

A New Absolute Proper Motion Determination of Leo I Using HST/WFPC2 Images and Gaia EDR3

The Astronomical Journal ◽

10.3847/1538-3881/ac30dc ◽

2021 ◽

Vol 163 (1) ◽

pp. 1

Author(s):

Dana I. Casetti-Dinescu ◽

Caitlin K. Hansen ◽

Terrence M. Girard ◽

Vera Kozhurina-Platais ◽

Imants Platais ◽

...

Keyword(s):

Proper Motion ◽

Milky Way ◽

Proper Motions ◽

Large Area ◽

Field Of Study ◽

Data Set ◽

Polar Structure ◽

The Galaxy ◽

The Absolute

Abstract We measure the absolute proper motion of Leo I using a WFPC2/HST data set that spans up to 10 yr to date the longest time baseline utilized for this satellite. The measurement relies on ∼2300 Leo I stars located near the center of light of the galaxy; the correction to absolute proper motion is based on 174 Gaia EDR3 stars and 10 galaxies. Having generated highly precise, relative proper motions for all Gaia EDR3 stars in our WFPC2 field of study, our correction to the absolute EDR3 system does not rely on these Gaia stars being Leo I members. This new determination also benefits from a recently improved astrometric calibration of WFPC2. The resulting proper-motion value, (μ α , μ δ ) = (−0.007 ± 0.035, − 0.119 ± 0.026) mas yr−1 is in agreement with recent, large-area, Gaia EDR3-based determinations. We discuss all the recent measurements of Leo I’s proper motion and adopt a combined, multistudy average of ( μ α 3 meas , μ δ 3 meas ) = ( − 0.036 ± 0.016 , − 0.130 ± 0.010 ) mas yr−1. This value of absolute proper motion for Leo I indicates its orbital pole is well aligned with that of the vast polar structure, defined by the majority of the brightest dwarf spheroidal satellites of the Milky Way.

The Distance to the Center of the Galaxy

10.1017/s0074180900096443 ◽

1987 ◽

Vol 115 ◽

pp. 554-555 ◽

Cited By ~ 2

Author(s):

M. J. Reid ◽

M. H. Schneps ◽

J. M. Moran ◽

C. R. Gwinn ◽

R. Genzel ◽

...

Keyword(s):

Proper Motion ◽

Radial Component ◽

Proper Motions ◽

Star Forming ◽

The Galaxy

The distance to a star forming region can be determined by measuring the proper motions within H2O maser clusters. If the motions of the maser spots are random, the distance can be determined by applying the technique known as statistical parallax. Alternatively, if organized motions are evident in the proper motions, one can model the source to estimate its the distance. Both methods rely on a comparison of the radial component of the motion (in km/s) and the proper motion on the plane of the sky (in milli-arcseconds/year).

The Tautenburg Part Of The Programme Studying The Main Meridional Section Of The Galaxy

10.1017/s0074180900140008 ◽

1988 ◽

Vol 133 ◽

pp. 451-454

Author(s):

E. Schilbach

Keyword(s):

Proper Motion ◽

Proper Motions ◽

Schmidt Telescope ◽

Meridional Section ◽

Mean Error ◽

The Galaxy ◽

The Mean

The programme for the determination of proper motions with reference to galaxies for 6000 stars on 17 fields near the main meridional section of the Galaxy is presented. For each field there are 2 or 3 first-epoch plates taken with the Tautenburg Schmidt-telescope before 1970. In preliminary investigations the mean error of an individual proper motion was found to be per century both for bright (8m–12m) and for faint (16m–18m) stars.

A survey of trigonometric parallaxes and proper motions with the UK Schmidt Telescope: I. Methods and first results for stars brighter than B = 14 in a field near the South Galactic Pole

International Astronomical Union Colloquium ◽

10.1017/s0252921100073917 ◽

1978 ◽

Vol 48 ◽

pp. 48

Author(s):

C. A. Murray ◽

P. M. Corben

Keyword(s):

Proper Motion ◽

Atmospheric Dispersion ◽

Random Errors ◽

Schmidt Telescope ◽

The South ◽

The Galaxy ◽

First Results ◽

Trigonometric Parallaxes ◽

Pilot Investigation ◽

The Uk

AbstractIn an attempt to investigate the statistics of stars in the solar neighbourhood, independent of the bias toward high velocity stars introduced by selection of stars with large proper motion, a major astrometric investigation is being carried out at RGO using U.K. Schmidt plates measured on the GALAXY machine.So far more than 15000 objects brighter than B = 18 in a field near the South Galactic Pole have been measured on more than 50 plates taken between 19 74 and 1977.This paper describes the methods of analysis and the results of a pilot investigation on nearly 900 stars with B < 14. The measurements show a very high degree of internal consistence, demonstrating the astrometric excellence of the U.K. Schmidt telescope and the GALAXY machine; random errors of measurement are found to be about ±0075 (=1.1.μm) per coordinate over the whole area (4° x 4°) measured, using a simple linear plate constant model for all plates. The external error of a single component of proper motion is estimated to be ± 0013 which is exactly consistent with the internal measurement error. The external error of a parallax in the present data is about ± 0018 whereas that predicted from the errors of measurement, and the self-consistency of two subsets of the data, is ± 0013; it is shown that the discrepancy can be largely accounted for by the random errors (± O11) in the B-V colours used in computing the effect of atmospheric dispersion, and should be reduced when better photometry becomes available.