Development Of Radio Astronomy Research Articles

Development of large-aperture radio telescopes and applications of coupled structural-electromagnetic theory

<p indent="0mm">The smooth operation of radio telescopes is essential in radio astronomy. This paper establishes the importance of radio telescopes via examples of the discovery of gravitational waves, the merger of neutron stars, and the first black hole photograph. As radio astronomy advances, radio telescopes require larger apertures and higher pointing accuracy, resulting in a closer structural-electromagnetic coupling. To solve the coupled structural-electromagnetic problem of radio telescopes, the development of a coupled structural-electromagnetic theory is key to the smooth and efficient operation of large-aperture radio telescopes. To this end, this paper describes the development of radio telescopes built and put into operation in the last decade, as well as those under construction and to be built, and emphasizes the importance of coupled structural-electromagnetic theory in the design, manufacture, and operation of radio telescopes. Then, the paper systematically summarizes the application of coupled structural-electromagnetic theory in radio telescopes. Finally, future research hotspots of electromechanical coupling are proposed based on the development of radio astronomy and the performance requirements of large-aperture radio telescope antennas.

THE HISTORY OF RADIO ASTRONOMY IN POLAND: FROM SOLAR PATROLS TO PULSARS AND VLBI

The development of radio astronomy in Poland took some time to occur, in view of the destruction of the country during World War II. Also, the shift of the country's borders in favor of the Soviet Union led to the loss of two important astronomy observatories: the historic centers of astronomy in Wilno and Lwόw. The relocation of these important astronomical centers to Toruń and Wrocław in the West needed considerable effort. Hence radio astronomy was a second priority as the optical astronomers had to become operational first. Nevertheless, in the 1950s groups in Krakόw and Toruń started to erect radio telescopes. In Krakόw solar radio astronomy became established. In Toruń, there were experiments with low frequency parabolic antennas. First, a 15-m dish was built, and later a 32-m dish became operational. In Krakόw the solar patrol continued and a LOFAR station was added. Contacts with radio observatories in other parts of the world were established. In 1988 a new regional university was established in Zielona Gόra, and a group involved in pulsar research was built up there.

Wilbur Norman Christiansen 1913 - 2007

W. N. (?Chris') Christiansen was an innovative and influential radio astronomy pioneer. The hallmarks of his long and distinguished career in science and engineering, spanning almost five decades, were his inventiveness and his commitment to, and success with, large-scale projects. These projects were the outcome of his innovative skill as physicist and engineer. Paralleling this was his equal commitment to forging strong international links and friendships, leading to his election as Vice-President of the International Astronomical Union for the years 1964 to 1970, as President of the International Union of Radio Science, URSI, from 1978 to 1981, and subsequently as Honorary Life President in 1984, and as Foreign Secretary of the Australian Academy of Science from 1981 to 1985. Major subsequent developments in radio astronomy and wireless communications on the global scene stand as a legacy to Chris's approach to his work and to the development of those who worked with him.

The development of radio astronomy

Following the detection of extraterrestrial radio waves in 1932 by Karl Jansky, radio astronomy developed quickly after World War II. It established itself soon as a new branch of astronomy with today's outstanding record in the detection of new phenomena in space. These have been honoured by a number of Nobel prizes. Radio astronomy largely depends on technical developments in receiver technology, antenna systems, electronics and computing power. Ever shorter wavelengths down to the submm-wavelength range became accessible, resulting in new exciting discoveries. However, now and in future care must be taken, in particular for the lower frequency range, of harmful man-made interferences, which might mask the weak signals from space. New international facilities with orders-of-magnitude higher sensitivity like ALMA and SKA are planned or under construction. Space-borne observatories like PLANCK will detect weak fluctuations of the cosmic microwave background, which will constrain cosmological models with an unprecedented accuracy.

The First 50 Years at Palomar: 1949–1999 The Early Years of Stellar Evolution, Cosmology, and High-Energy Astrophysics

PROLOGUE▪ Abstract In 1999 we celebrate the 50th anniversary of the initial bringing into operation of the Palomar 200-inch Hale telescope. When this telescope was dedicated, it opened up a much larger and clearer window on the universe than any telescope that had gone before.Because the Hale telescope has played such an important role in twentieth century astrophysics, we decided to invite one or two of the astronomers most familiar with what has been achieved at Palomar to give a scientific commentary on the work that has been done there in the first fifty years.The first article of this kind which follows is by Allan Sandage, who has been an active member of the staff of what was originally the Mount Wilson and Palomar Observatories, and later the Carnegie Observatories for the whole of these fifty years.The article is devoted to the topics which covered the original goals for the Palomar telescope, namely observational cosmology and the study of galaxies, together with discoveries that were not anticipated, but were first made at Palomar and which played a leading role in the development of high energy astrophysics.The Palomar work first showed how optical astronomy would be the key to our understanding of observations made in other parts of the electromagnetic spectrum, particularly at radio wavelengths and at X-ray energies. —Geoffrey Burbidge, EditorAn account is given of the history of two observational programs set for the Palomar 200-inch telescope, one by Walter Baade and the other by Edwin Hubble near the start of the scheduled operation of the telescope 50 years ago. The review is partly an assessment of whether, and how well, these programs have been carried to completion, and partly an account of the response of Palomar to new discoveries and developments not foreseen in 1950. Stellar evolution, the discovery of variations in the metallicity of stars of different populations, the chemical evolution of the Galaxy, the Cepheid P-L relation, the redshift-distance relation of the expanding universe, and the extragalactic distance scale are discussed as they relate to the predictions for progress on the programs set out by Baade and Hubble. Not foreseen was the invention and development of radio astronomy and high energy astrophysics, leading to the discovery of radio galaxies, quasars, and the gradual realization of violent events, both in stars and in galaxies. The review is highly restricted to these subjects, covering only three areas among the totality of the work in observational astrophysics studied during the first 50 years at Palomar.

The development of radio astronomy at Hartebeesthoek

The development of radio astronomy at the Hartebeesthoek Radio Astronomy Observatory in South Africa is described. The Hartebeesthoek site was established originally by NASA as one of three Deep Space Stations equipped with 26-m parabolic reflector antennas. It was first used for radio astronomy by South Africa in terms of the NASA “host nation agreement” which allowed for its use at times when the facility was not needed for its primary purpose of tracking space probes. After NASA withdrew from South Africa in 1975, the South African Council for Scientific and Industrial Research took over the site and the 26-m parabolic reflector antenna, which NASA had abandoned in position, and established it as a national observatory. The development of the facility to the stage where it could support a variety of observing programmes such as continuum observations and mapping, spectroscopy and pulsar timing is described as well as the role played by the Observatory in global programmes of very long baseline interferometry.

The Early Development of Radio Astronomy

The Early Development of Radio Astronomy

Recent developments in radioastronomy. II

For pt.I see ibid., vol.15, no.5, p.270 (1980). Topics covered include interstellar molecules, galactic structure, stellar evolution, binary pulsars and general relativity, extragalactic radio astronomy, source models, the double quasar and the allocation of frequency bands to radioastronomy.

Recent developments in radioastronomy. I

The past decade has seen considerable progress in radioastronomy both on the technical and the astrophysical fronts. To the familiar 'big dishes' have been added smaller, more accurately formed instruments capable of detecting signals on wavelengths as short as 1 mm and enabling astronomers to study the complex chemical structure of the interstellar medium through high frequency spectroscopy. As well as these developments there has been a major expansion in the use of the technique of interferometry and with newly developed image forming techniques, maps of radio sources are bing produced with definition as finite as a milliarc second. Radioastronomers are now able to peer into the regions of star formation and to chart the nuclei of external galaxies and quasars to explore the essential power sources of these fascinating objects. The author describes technical developments.

Does the Radio Spectrum have Room for Radio Astronomy?

In a technical sense radio astronomers do not use the radio spectrum; they are listeners only, and when the science began they had to listen in the quiet spaces between transmitting services. Radio astronomy was first recognized as a service by the International Telecommunications Union (ITU) in 1959, and the first frequency allocations were then made for it as a ‘passive’ service. In 1963 and 1971 further allocations and frequency protection were obtained at specialized World Administrative Radio Conferences (WARC). The allocations were required for two purposes: (i) to protect the frequencies of the most important spectral lines of atoms and molecules, and (ii) to provide a series of bands for continuum observations. The general protection so far provided has been vital to the growth of the science, and its continuation is of the highest priority to the future life and development of radio astronomy.

Radio Astronomy Revisited: A Reassessment of the Role of Competition and Conflict in the Development of Radio Astronomy

Radio Astronomy Revisited: A Reassessment of the Role of Competition and Conflict in the Development of Radio Astronomy

Radioastronomical investigations employing artificial satellites and space rockets

It is known that the introduction and development of radioastronomy were followed by marked advances in the study of the solar atmosphere, interstellar gas, galactic and extragalactic nebuli, cosmic radiations and so on. One of the reasons that radioastronomical methods proved effective was the possibility of employing very wide frequency ranges (approximately 11 octaves as compared with the range of 1 octave corresponding to the visible part of the spectrum). At the same time a further extension in the frequency spectrum available for observations is very desirable in radioastronomy. The only radical method of advancing in this direction resides in the use of artificial earth satellites and space rockets performing flights beyond the bo&daries of thd earth’s atmosphere, which impedes ground observations on wavelengths A 20-40 m. The paper(l) has already considered some of the possibilities of using artificial earth satellites for the purpose of radioastronomical investigations. Recent paperP4J have also dealt with this problem. The following paper considers radioastronomical methods of investigation employing artificial earth satellites, taking into account the propositions set out previously(14). Attention is turned mainly to the measurement principles, problems of instrumentation being touched on incidentally only in so far as necessary for clarifying the actual experimental possibilities.

Recent Developments in Radio Astronomy

Recent Developments in Radio Astronomy