Objective-Prism Radial Velocities at High Latitudes

1977 ◽  
pp. 77-77
Author(s):  
J. Stock ◽  
W. Osborn ◽  
A. R. Upgren
Keyword(s):  
Radial Velocities ◽  
High Latitudes ◽  
Objective Prism

scholarly journals Objective-Prism Radial Velocities at High Latitudes

1977 ◽  
Vol 4 (2) ◽  
pp. 77-77
Author(s):  
J. Stock ◽  
W. Osborn ◽  
A. R. Upgren
Keyword(s):  
Power Series ◽  
Spectral Line ◽  
High Latitude ◽  
Sufficient Accuracy ◽  
Radial Velocities ◽  
High Latitudes ◽  
Proper Motions ◽  
Third Order ◽  
Latitude Zone ◽  
Objective Prism

Stock and Osborn (1972, 1973) have shown that objective-prism spectra taken with a conventional prism may be measured to produce radial velocities of sufficient accuracy for statistical purposes. They are determined by means of a third-order power series in both x and y coordinates. The same spectral-line measures can also yield positions such that proper motions can be determined if first-epoch positions are also available. For many stars, both tangential and radial velocities can be obtained with about the same error which is of the order of ± 20 km/sec. The field distortions caused by the prism are large but are constant and predictable to the degree that measured residuals are similar in size to those for direct images (Stock and Upgren 1968). A survey of a high-latitude zone between −30° and −35° in declination is underway and a catalogue of about 3000 stars has already been compiled by Stock. For each star, the catalogue lists an accurate 1950 position, spectral and luminosity type, apparent photographic magnitude, relative radial velocity and its weight, and the number of plates on which the star was measured.

scholarly journals Study of Spectroscopic Binaries with the Objective Prism Method

1983 ◽  
Vol 62 ◽  
pp. 104-107
Author(s):  
Frank Gieseking
Keyword(s):  
Radial Velocity ◽  
Frequency Distribution ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Steep Decrease ◽  
Visual Magnitude ◽  
Objective Prism ◽  
The Individual ◽  
Large Telescopes

The frequency distribution of SB’s over apparent visual magnitude emerging from the catalogue of Batten et. al. (1978) shows a very steep decrease of the number of spectroscopically detected SB’s already for such bright stars of magnitude 7. Considering the number of all stars in the individual magnitude intervals, we find a kind of completeness parameter of the spectroscopic surveys: If we scale it somewhat optimistically at 100% between 0 and 3 mag, we see a 50% decrease of the completeness of our knowledge of stellar radial velocities already for stars fainter than 4.5 mag.This situation is mainly due to the fact that the measurement of radial velocities with conventional slit spectrographs is extremely laborious, requiring long exposure times at large telescopes for the exposure of only one spectrum at a time. – Therefore more efficient methods for radial velocity determinations of fainter stars are urgently needed.

A Critical Examination of the Stock Velocity Survey

1984 ◽  
Vol 88 ◽  
pp. 231-239
Author(s):  
Wayne Osborn ◽  
D.J. MacConnell
Keyword(s):  
Recent Work ◽  
Large Scale ◽  
Practical Problem ◽  
Large Magellanic Cloud ◽  
Radial Velocities ◽  
Critical Examination ◽  
Cluster Membership ◽  
Large Numbers ◽  
Observational Technique ◽  
Objective Prism

The possibility of determining stellar radial velocities for large numbers of stars from objective-prism plates was recognized soon after objective-prism spectroscopy became a common observational technique ; (Pickering, 1887). However, the initial investigations quickly revealed a serious practical problem: how does one determine the rest wavelength position in slitless spectra? This difficulty caused the objective-prism method of obtaining radial velocities to be neglected for many years. It was not until the second half of this century that the method saw a large-scale application. This was the work of Fehrenbach who developed a technique based on a specially designed zero-deviation prism, and successfully used it to isolate members of the Large Magellanic Cloud from foreground field stars (Fehrenbach 1947a, 1947b, 1948; Fehrenbach and Duflot 1970). The Fehrenbach technique has since been applied in a number of other studies; one can mention, as examples, recent work on spectroscopie binaries (Gieseking and Karimie 1982), on cluster membership (Gieseking 1980), and on velocity dispersions at intermediate galactic latitudes (Fehrenbach and Burnage 1982).

Coravel Radial Velocities of Supergiants in the Small Magellanic Cloud

1984 ◽  
Vol 88 ◽  
pp. 265-268
Author(s):  
E. Maurice ◽  
N. Martin ◽  
L. Prévot ◽  
E. Rebeirot
Keyword(s):  
South Africa ◽  
Velocity Field ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Radial Velocities ◽  
Small Magellanic Cloud ◽  
Objective Prism

Kinematical studies of the Magellanic Clouds began more than half a century ago, when Wilson, in 1918, first interpreted the gradient of the 17 radial velocities of gazeous nebulae in the Large Cloud in terms of rotation. In the case of the Small Magellanic Cloud, the first real attempt to understand the velocity field of this galaxy was performed by the Radcliffe astronomers (Feast et al., 1960, 1961). Their study was based on radial velocities of 40 stars and 13 HII regions.With the installation by ESO of an objective-prisme astrograph in South Africa, in 1961, and then of several larger telescopes in Chile in 1968, the number of measurements significantly increased for Magellanic objects, in particular in the SMC. In this galaxy, the objective-prism observations resulted in about 100 stellar radial velocities (Florsch, 1972a) of probable members. A compilation by Maurice (1979) of all then known slit-spectrograph radial velocities gave velocities for 80 supergiants, 35 HII regions and 12 planetary nebulae.

scholarly journals MRSP - The Muenster Redshift Project

1988 ◽  
Vol 130 ◽  
pp. 526-527
Author(s):  
P Schuecker ◽  
H Horstmann ◽  
W Seitter
Keyword(s):  
Software Package ◽  
Radial Velocities ◽  
Fair Agreement ◽  
Emission Lines ◽  
Astronomical Institute ◽  
The South ◽  
Objective Prism ◽  
Single Field

ESO/SRC-J-Atlas plates (film copies) and film copies of UK-Schmidt objective prism J-plates (dispersion 246nm/mm at Hγ) were scanned with the microdensitometer PDS 2020 GM and reduced automatically with the software package ADAS developed at the Astronomical Institute of Muenster University. In a single field (30 square degrees) near the South Galactic Pole 150 000 objects are found up to the limiting magnitude Stars and galaxies are separated. Algorithms for quasar search among the star-like objects are applied and radial velocities determined from the identified emission lines. Follow-up observations with the ESO 3.6m telescope show fair agreement between the redshifts determined from the objective prism plate and from the slit spectra.

scholarly journals Planetary Nebulae and the Galactic Bulge

1989 ◽  
Vol 131 ◽  
pp. 167-167
Author(s):  
M.W. Feast ◽  
T.D. Kinman ◽  
B.S. Lasker
Keyword(s):  
Planetary Nebulae ◽  
Good Evidence ◽  
Radial Velocities ◽  
The Sun ◽  
Galactic Bulge ◽  
Circular Velocity ◽  
Solar Motion ◽  
Objective Prism ◽  
Image Position

Fifteen new PN have been discovered in the region of Baade's Windows using an objective prism technique. Absolute spectrophotometry, excitation classes, radii and radial velocities have been obtained. Radial velocities were also measured for eight other PN in this region. After correction for solar motion and the circular velocity at the sun, the radial velocities of bulge PN (Vc) with |b| < 5°.5 show good evidence for a rotation of the bulge. If Vc=α + βΔℓ then,

scholarly journals Objective-Prism Redshifts of Faint Galaxies

1984 ◽  
Vol 78 ◽  
pp. 401-403
Author(s):  
J.A. Cooke ◽  
B.D. Kelly ◽  
S.M. Beard ◽  
D. Emerson
Keyword(s):  
Computer Software ◽  
Radial Velocities ◽  
Large Sample ◽  
Magnitude Range ◽  
Large Numbers ◽  
Objective Prism

AbstractA large sample of spectra of faint galaxies has been obtained using COSMOS measurements of UKST objective-prism plates. Computer software has been developed to obtain the radial velocities of large numbers of these galaxies automatically over a magnitude range of about B = 16 to 19. Initial tests have been performed on a sample of about 1400 galaxies from an area of about 5 x 4 degrees square.

Radial velocities from microdensitometer scans of objective-prism spectra

1981 ◽  
Vol 86 ◽  
pp. 246 ◽  
Author(s):  
E. W. Weis ◽  
A. R. Upgren ◽  
D. W. Dawson
Keyword(s):  
Radial Velocities ◽  
Objective Prism

A Search for High Velocity Stars

1984 ◽  
Vol 88 ◽  
pp. 183-186
Author(s):  
A. Florsch
Keyword(s):  
High Velocity ◽  
Galactic Plane ◽  
Photographic Plate ◽  
Radial Velocities ◽  
Density Limit ◽  
Measuring Devices ◽  
New Process ◽  
Objective Prism ◽  
Visual Measurements

Fehrenbach’s objective-prism technique for the measurement of radial velocities is well known and has already proved its efficiency. New measuring devices (MESUCOR, FENTOMIX at the O.H.P.) based on the correlation between records make the measurement more rapid and more accurate and will encourage others to use this method. An example is the Hipparcos radial-velocities program. But it is also true that this new process has its limits and does not permit one to get all the information which is on an objective-prism plate, for it is limited by the quality (principally the density) of the images. It will be necessary to continue with the classical visual measurements, especially if one wants to detect faint high-velocity stars quickly, which are often at the density limit of the photographic plate. We must keep in mind that the objective-prism technique is best for this purpose since a three or four hour exposure leads to a great number of spectra (about 60 near the pole, to 200 in the galactic plane in a field of 2X2 degrees).

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