scholarly journals The Discovery of Double Stars at Occultations

1983 ◽  
Vol 62 ◽  
pp. 63-72 ◽  
Author(s):  
David S. Evans
Keyword(s):  
Position Angle ◽  
Visual Observation ◽  
Double Star ◽  
Double Stars ◽  
Photoelectric Observations ◽  
Vector Separation ◽  
Successful Observation

When systematic photoelectric observations of occultations were started some dozen years ago it was realised that they yielded a significant crop of double star discoveries and observations. The limitations of the method were well recognised: only about ten percent of the area of the sky would ever be available and one could not choose which stars to be observed. Moreover the data obtained from a successful observation of a double star are less comprehensive than the normal visual observation. The result is the vector separation or the true separation projected along a line perpendicular to the actual lunar limb, that is the position angle of the point of occultation modified by the slope of the limb at that point.

scholarly journals Catalogue of Occultation Double Star Observations

1983 ◽  
Vol 62 ◽  
pp. 73-90
Keyword(s):  
Spectral Type ◽  
Position Angle ◽  
Double Star ◽  
Star Catalogue ◽  
Grade 3 ◽  
Vector Separation

The catalogue is divided into three sections: bright stars with magnitudes less than or equal to 6.7: other stars having numbers in the Smithsonian Astrophysical Star Catalogue with magnitudes greater than 6.7: and other stars with no SAO numbers, usually faint and with often only fragmentary information concerning their magnitudes or spectra.Each section has the following columns: SAO number, other name, magnitude, spectral type, run number of the observation, date in obvious coded form, grade — grade zero indicates no duplicity, grade 1 possible duplicity, grade 2 probable duplicity, and grade 3 certain duplicity. Grades are based on statements by observers. For grades other than zero the vector separation and its computed error are given in arc milliseconds. P.A. denotes the direction in which the vector separation is measured, that is the position angle on the lunar limb as modified by the slope deduced in favorable cases from the spacing of the diffraction bands on the occultation trace. The next column gives the limb slope and its error.

scholarly journals Systematic Errors in Double Star Observations

1992 ◽  
Vol 135 ◽  
pp. 311-313 ◽  
Author(s):  
Geoffrey G. Douglass ◽  
Charles E. Worley
Keyword(s):  
Root Mean Square ◽  
Proximity Effect ◽  
Position Angle ◽  
Systematic Errors ◽  
Double Star ◽  
Mean Square ◽  
Double Stars ◽  
Visual Double Stars ◽  
Systematic Effects

AbstractWe have examined the visual and speckle observations of visual double stars made by 31 experienced observers in order to evaluate possible systematic errors in these series. Using 57 “definitive” orbits, we find no appreciable errors in position angle. We do find systematic effects in separation for some observers, and, in particular, a “proximity” effect for measurements of pairs closer than 0″.5.Root-mean-square residuals are:

scholarly journals Detection of Double Stars with the Two-Color Refractometer

1983 ◽  
Vol 62 ◽  
pp. 28-35 ◽  
Author(s):  
James W. Christy ◽  
Dennis D. Wellnitz ◽  
Douglas G. Currie
Keyword(s):  
Position Angle ◽  
Angular Distance ◽  
Double Star ◽  
Measured Quantity ◽  
University Of Maryland ◽  
Additional Information ◽  
Double Stars ◽  
Color Differences ◽  
Nearby Stars ◽  
The University

AbstractAttempts to detect double stars are being made with the Two-Color Refractometer (TCR). The refractometer is an instrument developed by the Quantum Electronics Group of the University of Maryland to measure atmospheric refraction.During check-out observations using the U.S. Naval Observatory’s (USNO’s) 24“ reflecting telescope, the refractometer is being used to detect the astrometric separation of the ultraviolet and red photocenters of the combined light from a double star, differentially referenced to nearby stars. The refractometer contains two dispersive wedges which null the incoming dispersion; the positions of the wedges then provide a measure of the dispersion of the incoming light. The angular part of this measure immediately gives the position angle of the double. The angular distance between the two components of the pair is a combined function of the measured quantity and of the magnitude and color differences of the components of the double star, and is therefore obtainable only with additional information.

scholarly journals Double Star Astrometry with the Hipparcos Data

1995 ◽  
Vol 166 ◽  
pp. 69-76
Author(s):  
F. Mignard
Keyword(s):  
Position Angle ◽  
Double Star ◽  
Recognition Procedure ◽  
Double Stars ◽  
Multiple Stars ◽  
Relative Coordinates ◽  
Double And Multiple Stars

As we approach the final processing of the observations carried out by HIPPARCOS, in particular for the double and multiple stars, it is possible to provide reliable statistics on the number of such objects detected and on the quality of the relative and absolute astrometry and photometry. About 24 000 stars have been recognized as non-single, including 11 000 already known as double and multiple before the mission and 13000 discovered by Hipparcos. Also, a subset of 16 000 stars among the 24 000 have been successfully solved for their relative coordinates (position angle and separation) with an accuracy in the range of 3 to 30 mas, including 7000 new double stars. I outline in this paper the principle of the internal recognition procedure and present some statistics on the solution.

scholarly journals HIPPARCOS First Results in the Double Star Processing by the FAST Consortium

1992 ◽  
Vol 135 ◽  
pp. 403-411
Author(s):  
F. Mignard ◽  
M. Badiali ◽  
P.L. Bernacca ◽  
H. Bernstein ◽  
D. Cardini ◽  
...  
Keyword(s):  
Position Angle ◽  
Double Star ◽  
Double Stars ◽  
Multiple Stars ◽  
Relative Coordinates ◽  
First Results ◽  
Double And Multiple Stars ◽  
Quantitative Results ◽  
One Year

AbstractAfter the processing of one year of observations carried out by HIPPARCOS it is possible to provide quantitative results as to the number of new double and multiple stars to be detected and the real capacity of this mission to perform relative astrometry on double stars. We present and discuss the methods developed to this end and include the first results concerning the detection statistics and the determination of separation and position angle for double stars. About 16,000 stars have been recognized as non-single, including 9,000 already known as double and mutliple before the mission. Also, a subset of 10,500 stars have been successfully solved for their relative coordinates with an accuracy in the range of 3 to 10 mas.

scholarly journals First speckle interferometric measurements of binary stars at the Observatorio Astrofísico Guillermo Haro

2020 ◽  
Vol 495 (1) ◽  
pp. 806-815 ◽  
Author(s):  
C A Guerrero ◽  
F F Rosales-Ortega ◽  
G Escobedo ◽  
J Martínez ◽  
E Castillo ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Binary Stars ◽  
Position Angle ◽  
Double Star ◽  
Fast Imaging ◽  
Star Catalog ◽  
Double Stars ◽  
New Instrument ◽  
Imaging Camera ◽  
Magnitude Difference

ABSTRACT In this paper, we present the first multiband speckle interferometric measurements of binary stars performed using the 2.1 m telescope of the Observatorio Astrofísico Guillermo Haro, Cananea, Sonora, México. We describe here FICCO: Fast Imaging Camera for Cananea Observatory, a new instrument developed to perform speckle observations from the Northern Hemisphere. We tested this new instrument with objects from the Washington Double Star Catalog, that were observed during three runs allocated in 2019. We report 480 astrometric measurements of 138 pairs, with angular separations ranging from 0.06 to 5.76 arcsec, including 347 measurements with separations smaller than 1 arcsec. We estimated a mean error in separation of 14 mas, 1.6° in position angle, and 0.45 mag for the magnitude difference. We confirmed 12 double stars discovered by Hipparcos. Finally, we present a correction to four previously published orbital solutions of visual binaries.

scholarly journals SUSI’s Potential for Double Star Research

1992 ◽  
Vol 135 ◽  
pp. 521-526
Author(s):  
John Davis
Keyword(s):  
Angular Resolution ◽  
Double Star ◽  
Double Stars ◽  
Stellar Interferometer ◽  
New Instrument

AbstractThe Sydney University Stellar Interferometer (SUSI) is currently undergoing commissioning and will soon commence its astronomical program in which observations of double stars will form a major component. With its 640-m long North–South array of input siderostats, the new instrument will have unprecedented angular resolution.

scholarly journals Photometric Observations of Three Double Stars by the Occultation Method — Comparison with Interferometric Results and with Preliminary Results of HIPPARCOS

1992 ◽  
Vol 135 ◽  
pp. 546-548
Author(s):  
M. Froeschlé ◽  
C. Meyer
Keyword(s):  
Diffraction Pattern ◽  
Method Comparison ◽  
Short Description ◽  
Double Star ◽  
Preliminary Results ◽  
Double Stars ◽  
Photometric Observations

AbstractWe first briefly recall the geometry of the occultation of a double star by the Moon’s edge. Then we give a short description of the principle of the formation of the diffraction pattern. We present the results for three double stars and compare them with those obtained by other methods.

scholarly journals Astrometric Application of the Photoelectric Scanning Technique

1971 ◽  
Vol 5 ◽  
pp. 20-21
Author(s):  
Otto G. Franz
Keyword(s):  
Data Acquisition ◽  
National Science Foundation ◽  
Data Acquisition System ◽  
Double Star ◽  
Acquisition System ◽  
National Science Foundation Grant ◽  
Double Stars ◽  
Scanning Technique ◽  
National Science ◽  
Associated Data

AbstractA new photoelectric area scanner, designed primarily for observations of double stars, has been put into routine use at the Lowell Observatory. A description of the scanner and of the associated data acquisition system is given. The procedure of measuring the relative positions of double star components is described and the accuracy obtainable by this method is discussed. This contribution and a subsequent one (p. 170) will appear jointly under the title 'A Photoelectric Area Scanner for Astrometry and Photometry of Double Stars' in Lowell Observatory Bulletin No. 154. This work has been supported by National Science Foundation Grant GP-6983.

scholarly journals Speckle Interferometry of Double Stars from the Southern Hemisphere

1995 ◽  
Vol 166 ◽  
pp. 392-392
Author(s):  
E. Horch ◽  
W. F. Van Altena ◽  
T. M. Girard ◽  
C. E. López ◽  
O. Franz
Keyword(s):  
Southern Hemisphere ◽  
Main Sequence ◽  
Speckle Interferometry ◽  
Double Star ◽  
Lower Portion ◽  
Stanford University ◽  
Imaging Device ◽  
Double Stars ◽  
Microchannel Array

We have started a new program of double star observations in the southern hemisphere which utilizes the technique of speckle interferometry. Observations are made using the Stanford University speckle interferometer on the 76-cm reflector at the Cesco Observatory at El Leoncito, Argentina (jointly run by Universidad Nacional de San Juan and Yale Southern Observatory), although we will also have access to larger aperture telescopes. The Stanford system, formerly used at Lick Observatory, is on long term loan to us from Dr. Gethyn Timothy and features a multi-anode microchannel array (MAMA) detector as the imaging device. This new program of double star research will help alleviate the continuing problem of fewer speckle observations in the southern hemisphere. In combination with other data such as the eyepiece interferometer measures of Finsen and Hipparcos parallaxes, it should also eventually contribute to a better understanding of the lower portion of the main sequence mass-luminosity relation.

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