Space Distribution and State of Motion of the Interstellar Matter as Revealed from Radio-Astronomical Observations

1971 ◽  
pp. 145-151 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Space Distribution ◽  
Interstellar Matter ◽  
Astronomical Observations

FRACTAL ASPECTS OF INTERSTELLAR CLOUDS

Fractals ◽  
1993 ◽  
Vol 01 (04) ◽  
pp. 930-938 ◽  
Author(s):  
THOMAS ZIMMERMANN ◽  
JÜRGEN STUTZKI
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Interstellar Matter ◽  
Interstellar Clouds ◽  
Astronomical Observations ◽  
Self Similar ◽  
Interstellar Molecular Clouds

Interstellar matter consisting of gas and dust shows structures which appear to have self-similar projected shapes, similar to the properties of terrestrial clouds. Moreover, the completely different physics in these interstellar clouds reveals several additional self-similar/fractal aspects which are investigated by extensive astronomical observations, aiming especially at a better understanding of the processes of star formation which take place in interstellar molecular clouds.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

The Role of VLBI in the Establishment of Coordinate Systems

1975 ◽  
Vol 26 ◽  
pp. 293-295 ◽  
Author(s):  
I. Zhongolovitch
Keyword(s):  
General Solution ◽  
Future Development ◽  
Rational Approach ◽  
Radio Telescopes ◽  
Coordinate Systems ◽  
Tectonic Plates ◽  
Astronomical Observations ◽  
Optical Instruments ◽  
Fundamental Polyhedron

Considering the future development and general solution of the problem under consideration and also the high precision attainable by astronomical observations, the following procedure may be the most rational approach:1. On the main tectonic plates of the Earth’s crust, powerful movable radio telescopes should be mounted at the same points where standard optical instruments are installed. There should be two stations separated by a distance of about 6 to 8000 kilometers on each plate. Thus, we obtain a fundamental polyhedron embracing the whole Earth with about 10 to 12 apexes, and with its sides represented by VLBI.

Representation of information in SEM by equal signal lines

1978 ◽  
Vol 36 (1) ◽  
pp. 144-145
Author(s):  
E. Rau ◽  
N. Karelin ◽  
V. Dukov ◽  
M. Kolomeytsev ◽  
S. Gavrikov ◽  
...  
Keyword(s):  
Electronic System ◽  
Space Distribution ◽  
Specimen Surface ◽  
Universal Method ◽  
Base Level ◽  
Signal Value ◽  
Information Signal ◽  
Fixed Base ◽  
Scanning Line ◽  
Amplitude Analyzer

There are different methods and devices for the increase of the videosignal information in SEM. For example, with the help of special pure electronic [1] and opto-electronic [2] systems equipotential areas on the specimen surface in SEM were obtained. This report generalizes quantitative universal method for space distribution representation of research specimen parameter by contour equal signal lines. The method is based on principle of comparison of information signal value with the fixed levels.Transformation image system for obtaining equal signal lines maps was developed in two versions:1)In pure electronic system [3] it is necessary to compare signal U (see Fig.1-a), which gives potential distribution on specimen surface along each scanning line with fixed base level signals εifor obtaining quantitative equipotential information on solid state surface. The amplitude analyzer-comparator gives flare sport videopulses at any fixed coordinate and any instant time when initial signal U is equal to one of the base level signals ε.

Relationship between Faithfulness and Preference of Stars in a Planetarium

2019 ◽  
Vol 2 (1) ◽  
pp. 10402-1-10402-11
Author(s):  
Midori Tanaka ◽  
Takahiko Horiuchi ◽  
Ken’ichi Otani
Keyword(s):  
Light Source ◽  
Preference Rating ◽  
Experimental Procedure ◽  
Male And Female ◽  
Astronomical Observations ◽  
Low Luminance ◽  
Projection Pattern ◽  
The Relationship ◽  
Star Field

Abstract A planetarium imitates a starry sky with physical and technical limitations using a dome, projector, and light source. It is widely used for entertainment, and astronomy and physics educations. In our previous study, we investigated the evaluation for faithful reproduction of a star field in a planetarium by performing psychometric experiments with 20 observers for plural projection patterns with different reproduction factors (color, luminance, and size of projected stars). In this study, we investigate the relationship between faithfulness and preference of a star field in a planetarium through a psychometric experiment with 47 observers. The experimental procedure followed the previous study. The rating of faithfulness improved for the projection pattern with a smaller star size. For the preference evaluation, the projection pattern with low luminance significantly lowered the preference rating. The results of the experiment indicate that the preferable star reproduction was different between male and female observers, whereas the faithful star reproduction was not significantly different in the evaluations between male and female observers. The male observers sought a faithful star reproduction as the preferred reproduction. In contrast, the female observers did not feel the faithful star reproduction preferable, and evaluated the more brilliant star reproduction as the preferred reproduction. These results were not dependent on the experience in astronomical observations.

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