A New Very High Angular Resolution Stellar Interferometer

1985 ◽  
Vol 6 (1) ◽  
pp. 38-43 ◽  
Author(s):  
J . Davis ◽  
W . J . Tango
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Stellar Interferometer ◽  
Wide Range ◽  
New Instrument ◽  
The University ◽  
Very High

AbstractThe Chatterton Astronomy Department of the University of Sydney is proposing the construction of a very high angular resolution stellar interferometer of major astronomical and international significance. Based on the prototype modern Michelson stellar interferometer which the Department has developed, the new instrument will be used in a wide range of astrophysical programmes. The siting, specification, design and costing of the instrument are outlined.

scholarly journals Introduction to the Joint Commission Meeting on High Resolution Imaging from the Ground

1989 ◽  
Vol 8 ◽  
pp. 545-546
Author(s):  
John Davis
Keyword(s):  
High Resolution ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
High Resolution Imaging ◽  
Wide Range ◽  
High Resolution Images ◽  
Resolution Imaging ◽  
Optical Wavelengths ◽  
To Come ◽  
Very High

As a result of advances in instrumentation and techniques, from radio through to optical wavelengths, we have before us the prospect of producing very high resolution images of a wide range of objects across this entire spectral range. This prospect, and the new knowledge and discoveries that may be anticipated from it, lie behind an upsurge in interest in high resolution imaging from the ground. Several new high angular resolution instruments for radio, infrared, and optical wavelengths are expected to come into operation before the 1991 IAU General Assembly.

scholarly journals Measuring Stars with High Angular Resolution: Current Status and Future Prospects

1985 ◽  
Vol 111 ◽  
pp. 193-208
Author(s):  
John Davis
Keyword(s):  
Angular Resolution ◽  
Modern Technology ◽  
Surface Fluxes ◽  
Current Status ◽  
High Angular Resolution ◽  
Long Baseline ◽  
Stellar Interferometer ◽  
Current State ◽  
The University

The current state of knowledge of angular diameters of stars is reviewed and, based on this review and the requirements for the determination of surface fluxes, effective temperatures, radii and masses, targets of sensitivity, angular resolution and accuracy for future programs of stellar angular diameter measurements are established. Long baseline interferometry is the only technique with the potential to meet all the targets. The necessary improvements in sensitivity, angular resolution and accuracy are promised by the approach adopted in the modern Michelson stellar interferometer under development at the University of Sydney and the prototype instrument, which is currently nearing completion, is briefly described to illustrate how the atmospheric and mechanical problems which have inhibited the development of amplitude interferometry may be overcome using modern technology. This program together with the developments taking place at CERGA lead to the conclusion that the prospects for contributions by high angular resolution measurements to the determination of fundamental stellar quantities during the next decade are excellent.

scholarly journals Binary Star Observations with the Multi-Aperture Amplitude Interferometer

1983 ◽  
Vol 62 ◽  
pp. 202-216
Author(s):  
Douglas G. Currie
Keyword(s):  
Angular Resolution ◽  
Binary Star ◽  
High Angular Resolution ◽  
Next Generation ◽  
General Science ◽  
Multiple Star ◽  
University Of Maryland ◽  
Basic Goal ◽  
The University ◽  
Very High

The basic goal of the Amplitude Interferometer Program at the University of Maryland has been to achieve very high angular resolution, far beyond the angular resolution which is normally permitted by the Earth’s atmosphere. This program is primarily directed to the observation of objects of astrophysical and astrometrical interest.The initial general science objective has been the measurement of the angular diameters of various single stars at various wavelengths. As shall be discussed later, this has been achieved on the current equipment.The second objective of the Amplitude Interferometer Program is the study of binary and multiple star systems. Some initial tests have been conducted to validate the approach and the expected accuracy using the existing Amplitude Interferometer (AI). However, detailed tests and/or a regular observing program require the multiplexing capablity of the next generation Amplitude Interferometer (the Multi-Aperture Amplitude Interferometer) in order to have a reasonable observing efficiency for the use of the telescopes which would be involved

TEM study of boron additions to cobalt aluminide

1988 ◽  
Vol 46 ◽  
pp. 546-547
Author(s):  
Gerald B. Feldewerth
Keyword(s):  
High Temperature ◽  
Turbine Engines ◽  
Major Drawback ◽  
University Of Missouri ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Wide Range ◽  
Ordered Alloys ◽  
The University ◽  
Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

Small-Angle Electron Scattering (SAES) of Polymers

1985 ◽  
Vol 43 ◽  
pp. 78-79
Author(s):  
Ralph Oralor ◽  
Pamela Lloyd ◽  
Satish Kumar ◽  
W. W. Adams
Keyword(s):  
Electron Scattering ◽  
Small Angle ◽  
Angular Resolution ◽  
Structural Features ◽  
Objective Lens ◽  
High Angular Resolution ◽  
Push Button ◽  
First Case ◽  
Diffraction Mode ◽  
Very High

Small angle electron scattering (SAES) has been used to study structural features of up to several thousand angstroms in polymers, as well as in metals. SAES may be done either in (a) long camera mode by switching off the objective lens current or in (b) selected area diffraction mode. In the first case very high camera lengths (up to 7Ø meters on JEOL 1Ø ØCX) and high angular resolution can be obtained, while in the second case smaller camera lengths (approximately up to 3.6 meters on JEOL 1Ø ØCX) and lower angular resolution is obtainable. We conducted our SAES studies on JEOL 1ØØCX which can be switched to either mode with a push button as a standard feature.

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 The circumstellar discs of Be stars

2010 ◽  
Vol 6 (S272) ◽  
pp. 325-336 ◽  
Author(s):  
Alex C. Carciofi
Keyword(s):  
Angular Resolution ◽  
Central Star ◽  
High Angular Resolution ◽  
Be Stars ◽  
Keplerian Orbit ◽  
Physical Processes ◽  
Simple Description ◽  
Model Predictions ◽  
Mass Ejection ◽  
Very High

AbstractCircumstellar discs of Be stars are thought to be formed from material ejected from a fast-spinning central star. This material possesses large amounts of angular momentum and settles in a quasi-Keplerian orbit around the star. This simple description outlines the basic issues that a successful disc theory must address: 1) What is the mechanism responsible for the mass ejection? 2) What is the final configuration of the material? 3) How the disc grows? With the very high angular resolution that can be achieved with modern interferometers operating in the optical and infrared we can now resolve the photosphere and immediate vicinity of nearby Be stars. Those observations are able to provide very stringent tests for our ideas about the physical processes operating in those objects. This paper discusses the basic hydrodynamics of viscous decretion discs around Be stars. The model predictions are quantitatively compared to observations, demonstrating that the viscous decretion scenario is currently the most viable theory to explain the discs around Be stars.

Fused silica segments: a possible solution for x-ray telescopes with very high angular resolution like Lynx/XRS

2017 ◽  
Author(s):  
Bianca Salmaso ◽  
Stefano Basso ◽  
Marta M. Civitani ◽  
Mauro Ghigo ◽  
Joanna Holyszko ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Fused Silica ◽  
High Angular Resolution ◽  
X Ray ◽  
Very High

scholarly journals Early Results from the HAO/NSO Advanced Stokes Polarimeter

1993 ◽  
Vol 141 ◽  
pp. 173-176 ◽  
Author(s):  
B. W. Lites ◽  
D. F. Elmore ◽  
S. Tomczyk ◽  
P. Seagraves ◽  
A. Skumanich ◽  
...  
Keyword(s):  
Field Strength ◽  
Quantitative Measurement ◽  
Angular Resolution ◽  
Outer Edge ◽  
Disk Center ◽  
High Angular Resolution ◽  
Vertical Field ◽  
Early Results ◽  
New Instrument ◽  
Mixed Polarity

AbstractThe Advanced Stokes Polarimeter is a new instrument dedicated to quantitative measurement of vector magnetic fields in lines formed at several heights in the solar atmosphere at high angular resolution. We present results for a small, symmetric sunspot observed under good seeing conditions near disk center on 25 March 1992. The narrow penumbral “spines” of more vertical field reported by Degenhardt and Wiehr (1991) and Title et al. (1992) are clearly seen in these observations. These spines are characterized by higher field strength than the surrounding penumbra. The inferred field azimuth indicates that these spines flare out with height, as would be expected of stronger field intrusions within the background penumbral field. The observations indicate the penumbral field “canopy” extends well beyond the outer edge of the penumbra. Outside of the sunspot, the small flux elements of mixed polarity are nearly vertical in orientation.

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