Observations Of Double Stars Research Articles

Resolute and undertaking characters: the lives of Wilhelm and Otto Struve

Wilhelm Struve founded a dynasty of astronomers that lasted into the fifth generation. This book follows the fortunes of the first three generations: Wilhelm himself was an outstanding astronomer and geodesist, famous for his pioneering observations of double stars - observations whose quality had not been surpassed until the development of modern methods of instrumental observational analysis. He is also well known as one of the three men who - almost simultaneously - succeeded in measuring the distance to one of the fixed stars. He founded the great observatory of Pulkovo, just outside modern Leningrad, and was succeeded as Director of the institution by his son Otto, who forms the subject of the second part of the book. Otto, too, was a famous observer of double stars and a great practitioner of the fundamental astronomy of the nineteenth century.

Are double star observations the most suspicious ones in the Paris astrolabe programme?

Are double star observations the most suspicious ones in the Paris astrolabe programme?

A Very Special Catalogue: The Hipparcos Input Catalogue

The various characteristics of the HIPPARCOS Input Catalogue are described:–How to select 110 000 stars for HIPPARCOS observation from the 210 000 proposed stars, taking into account the following sometimes conflicting requirements : satisfy a maximum of scientific programmes and respect the observational constraints inherent in the HIPPARCOS satellite operation ?–What are the present results regarding the principal astrometric programmes ?–How to process the specific problems which are raised by the HIPPARCOS observation of double and multiple stars and of stars in dense areas ?–Which compilations and observations have been undertaken and are in progress within the frame of the Input Catalogue preparation ? What will be the quality of the final data ?Finally, the contents of the catalogues and annexes that will be published are briefly presented.

Micrometer observations of double stars and new pairs. XIII

Micrometer observations of double stars and new pairs. XIII

Micrometer observations of double stars and new pairs. XII

view Abstract Citations (8) References (2) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Micrometer observations of double stars and new pairs. XII. Heintz, W. D. Abstract Measurements of 2132 pairs and 103 double stars, obtained in both the Northern and Southern Hemispheres in the period June 1982 to September 1984, are listed in a table. The observations were carried out using the Swarthmore College 61-cm refractor, and the 100 and 91 cm telescopes of the Cerro Tololo Inter-American Observatory. Corrections to the IDS catalog (1961 version) are given for some of the fainter stars in the survey. Publication: The Astrophysical Journal Supplement Series Pub Date: July 1985 DOI: 10.1086/191048 Bibcode: 1985ApJS...58..439H Keywords: Astrometry; Astronomical Coordinates; Double Stars; Micrometers; Star Distribution; Astronomical Catalogs; Stellar Magnitude; Astronomy full text sources ADS | data products SIMBAD (145) Related Materials (7) Part 1: 1956MNRAS.116..248H Part 2: 1978AJ.....83..436M Part 3: 1984AJ.....89..876M Part 4: 1978ApJS...37..343H Part 5: 1980ApJS...44..111H Part 6: 1983ApJS...51..249H Part 8: 1987ApJS...65..161H

On the observation of double stars for the determination of their proper motions

The state of meridian observations of the DS program is reported. The program contains close double stars whose precise positions can be determined by the visual method only. In some declination zones these stars have been observed at a few observatories of the USSR and in Strasbourg, Santiago de Chile and Beograd. The importance of further DS observations, particularly in the southern sky, is stressed.

The Discovery of Double Stars at Occultations

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.

First Results Concerning the Capability of a TV Camera for Double Star Observations

SummaryThe results of some first laboratory analysis of double star images recorded with a TV camera are presented.The camera – already in use since a few years for occultation-timings has been described earlier. For double star observations, the equipment has been completed by a video disc memory, a video analyser with analogic-digital converter and a small programmable calculator.Details are given about this equipment and its possibilities. The reduction method in its present state is described as well as some first results. These show a very good internal agreement leading to a high promising new observational technique.

IMPROVED ORBITS OF THE VISUAL BINARY DELTA EQUULEI.

ABSTRACT Additional coude' spectrograms of Equ combined with analysis of the available visual double star observations allow us to determine the properties of this F7 V system with high precision. The average values of the mass and visual absolute magnitude are 1.19 'A)' , and , respectively. Key words: stellar masses-stellar luminosities-visual binary stars-spectroscopic binary stars

Derivation of angular diameters of stars from lunar occulations

AbstractA short description of the theoretical basis of the method is given, followed by the results of the diameter observations of four giant stars obtained in 1964 and 1971 with the 30‐cm refractor of the Lohrmann Observatory. The angular diameters found are as follows: n Gem (M3III) 0″.0095 ± 0″.0015; μ Gem (M3III). 0′.0135 ± 0′.0025; 187 B. Gem (K5) 0′.0029 ± 0″.0001; 31 Leo (K4III) 0″.0039 ± 0″.0002. In two tables a general view on the diameter and double star observations using occultation technique published until the middle of 1974 is given.

M Dwarfs and the Missing Mass

This is a short report on our study of the M dwarfs in the South Galactic Pole region in connection with the problem of the missing mass and the luminosity function of intrinsically faint stars. The M-type stars found in our objective prism survey with the Lembang Schmidt telescope have been studied in collaboration with Dr. D.H.P. Jones for the discrimination between dwarfs and giants. Furthermore, these stars are all observed photo-electrically in Kron’s R, I-system at La Silla, Chile. Results of the work will be published soon. A blink survey has been initiated at Nymegen using copies of red and blue Mt. Palomar Sky survey plates to find faint red stars in the S.G.P.-region.Kumar has put forward the idea that Oort’s missing mass is to be found as a large number of very low mass stars (0.01-0.07 Mθ) in the solar neighbourhood. His idea is backed up by the fact that stars within this mass range have been found by double star observers. Staller suggested that the low velocity M dwarfs found in the directions of the galactic poles represent Kumar’s very low mass stars. This proposal is ment not only for giving an answer to the problem of the missing mass but also for those problem connected with the observed small velocity dispersion (10-15 km/sec) of the low velocity M dwarfs. Staller estimated the contracting and cooling times of these stars to be about 5 x 108 to 109 years. In the lifetime of our galaxy (about 10 years) 10 to 20 generations of these low mass stars have been created and evolve to very faint degenerated black dwarfs. The mass density of these stars, in the solar neighbourhood, will be large enough to solve the problem of the missing mass. The stars we observe at present as low velocity M stars are genuinely young red stars, and their small velocity dispersion will therefore not contradict Spitzer and Schwarzschild’s mechanism for the creation of “velocity dispersion by encounters with interstellar clouds. The age of the older very faint black dwarfs is comparable to that of our galaxy. These stars should therefore have a large velocity dispersion. Staller has shown that on the average the low mass stars have a velocity dispersion larger than 21 km/sec, and therefore the whole group of low mass stars is satisfying Toomre’s stability criterion for the galactic disk, such as newly derived by Biermann.

Photometric observations of visual double stars by the area scanning technique

UBV magnitude differences in visual binaries are presented and their accuracy is discussed. Typical observed image profiles of double stars, including sample profiles of Antares, are shown.

Photometric Observations of Visual Double Stars by the Area Scanning Technique

AbstractUBV magnitude differences in visual binaries are presented and their accuracy is discussed. Typical observed image profiles of double stars, including sample profiles of Antares, are shown. This contribution will appear jointly with the earlier one (p. 20) in Lowell Obs. Bull., No. 154. The work has been supported by NSF Grant GP-6983.

Astrometric application of the photoelectric scanning technique

A 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.

Astrometric Application of the Photoelectric Scanning Technique

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.

Photographic observations of double stars

Photographic observations of double stars

New telescope

The University of Chicago has announced that it will construct a 40‐inch reflecting telescope at its Yerkes Observatory in Williams Bay, Wis. Costs will be covered by a $176 000 grant from the National Science Foundation. One of the stated uses for the new instrument will be the observation of variable stars and double stars. Studies of this type, to be satisfactory, must be continued for long periods of time, which is usually not possible at the few larger instruments in the world.

Photometric Observations of Visual Double Stars by the Area Scanning Technique

AbstractUBV magnitude differences in visual binaries are presented and their accuracy is discussed. Typical observed image profiles of double stars, including sample profiles of Antares, are shown.This contribution will appear jointly with the earlier one (p. 20) inLowell Obs. Bull., No. 154. The work has been supported by NSF Grant GP-6983.

Astrometric Application of the Photoelectric Scanning Technique

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’ inLowell Observatory BulletinNo. 154. This work has been supported by National Science Foundation Grant GP-6983.

THE ROLE OF THE INTERFEROMETER IN DOUBLE-STAR ASTRONOMY

Several different types of interferometers have been proposed for observing visual double stars, but the only one that has been used to any great extent is the double-slit instrument pioneered at the Mount Wilson Observatory by Michelson, Anderson, and Merrill. The principle of this instrument is too well known to require detailed description here ; it will be sufficient to remark that if a diaphragm consisting of two symmetrical slits is placed in the optical train of a telescope the usual diffraction disk is replaced by a much larger elongated disk crossed by a set of parallel interference fringes. With a suitable choice of slit separation the spacing of adjacent bright and dark fringes may be made considerably smaller than the radius of the first dark ring of the full-aperture disk, with a consequent gain in resolving power in the direction normal to the fringes. In the limit, with infinitely narrow slits spaced the equivalent of the diameter of the object glass, the resolving power is theoretically increased by a factor of 2.44. It is important to note that we have achieved a gain in resolving power in one direction at the expense of a loss in the direction at right angles, and as a result we can no longer see a close pair as double but must infer its duplicity from the variation in the appearance of the fringes as we rotate in position angle. Only a few double-star observers have made systematic use