A radio telescope is similar to an optical telescope; however, instead of gathering light, the instrument gathers radio waves. Radio waves from space have a much longer wavelength than light, so radio telescopes need to be much larger than optical telescopes to achieve a similar resolution. “Resolution” is a description of the ability to distinguish between two closely spaced sources. The size of the collecting area of the telescope also governs its sensitivity, which determines the ability to detect weak radio signals. The terms radio telescope and aerial (or antenna) are often used interchangeably. Radio telescope may also refer as well to the whole system, including the receiving and signal processing systems.
The most basic type of radio telescope is a simple dipole linked to a receiver. A dipole is a pair of metal rods that collect the radio signal, with a size of half a wavelength. The half wavelength is used because this length has a natural reso- nance to the radio waves which excite electrical currents in the metal rods. This electrical signal is then ampliﬁed in a receiver and passed to a display or recording system. Most early radio telescopes used a simple paper chart recorder to record the intensity of the received signal as a function of time. Dipoles are often used in conjunction with a set of director rods, which are slightly smaller, and a reﬂector rod which is slightly larger. These “director” and “reﬂector” rods help focus the radio waves on the receiving dipole. The Yagi-Uda aerial was invented in 1921 by two prominent Japanese electrical engineers, Hydetsugu Yagi (1886–1976) and Shintaro Uda (1896–1976), often simply referred to as a Yagi aerial. This type of aerial will be familiar to the reader as the type used on household rooftops to receive analogue TV signals (see Fig. A.1).
© Springer International Publishing AG 2017 169 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 170 Appendix A: What Is a Radio Telescope?
Fig. A.1 A Yagi-Uda aerial commonly used to receive analogue TV signals. The ﬁrst three rods are directors which are slightly smaller than the half-wave length receiver rod. The ﬁnal rod is the reﬂector, which is slightly larger. The cable leading from the dipole rods to the receiver is visible (Source: Wikipedia)
Fig. A.2 A basic “dish”-type aerial. This aerial collects the incoming radio waves and focuses them on a receiver. This antenna is the same type of aerial used for satellite TV dishes
Dipole arrays can be used in many different conﬁgurations. When installed with reﬂecting backing screens, the aerial is referred to as a “broadside” array. The ﬁrst radio telescope was used by Karl Jansky in the early 1930s and was a complex type of dipole array called a Bruce Curtain aerial (see Chap. 2, Fig. 2.2). The dipoles were large as the observing wavelength was 14.6 m (frequency 20.5 MHz). Appendix A: What Is a Radio Telescope? 171
Dish Aerials or Antennas
Perhaps the most familiar type of aerial is the dish type which is also used for satellite TV antennas. The dish reﬂects the incoming radio wave to a receiver at the focal point of the parabolic shaped dish (see Fig. A.2), an analogue of a reﬂecting optical telescope. The resolution of the dish-type radio telescope is dependent on the diameter of the dish being used and must be larger than the wavelength of the radio waves being observed: the bigger the dish, the better the resolution. The diameter of the dish is referred to as the aperture, with the dish being a type of ﬁlled aperture telescope. This aerial was the type of radio telescope built by Grote Reber in 1937 (see Chap. 2, Fig. 2.3). One of the beneﬁts of the dish aerial is that it can be used to observe at different frequencies simply by changing the receiver at the prime focus of the aerial. Like optical telescopes, most dish-type radio telescopes have a mounting that allows them to track a source as it moves across the sky due to the rotation of the
Fig. A.3 The Five-hundred-metre Aperture Spherical Telescope (FAST) in China. The receiver is suspended at the prime focus point by cables from the surrounding towers. It began observations in September 2016 (Credit Xinhau) 172 Appendix A: What Is a Radio Telescope? earth. Unfortunately, there is a structural size limit (~100 m) in the construction of large dish-type aerials; for such structures, gravity distorts the surface of the dish, limiting the high-frequency use of the antenna as the astronomical object moves over the sky. To overcome some of these limitations, the largest dish-type radio telescopes, such as the recently commissioned Five-hundred-metre Aperture Spher- ical Telescope (FAST) built in China, are ﬁxed in place (see Fig. A.3). FAST was built in a natural sinkhole in the ground pointing straight up, relying on the earth’s rotation and the active adjustment of reﬂector panels and receiver feed point to observe a limited portion of the sky. This instrument also uses a spherical reﬂecting surface for simplicity of construction rather than a parabolic surface.
Beamwidth of a Radio Telescope
All aerials have directional sensitivity. A dipole is most sensitive when the rods are at right angles to the incoming wavefront; however, the sensitivity is bidirectional and so reﬂectors are used to reduce unwanted signals. A dish is naturally unidirec- tional and most sensitive when pointed directly at the radio source. The electrical response of the incoming radio waves can be measured by the dish. The aerial response pattern is referred to as the beam pattern or lobe response. The beamwidth is normally deﬁned as the angular distance between two points either side of the maximum response where the signal falls to half of the maximum power. A small dish operating at metre wavelengths will have a beamwidth of a few tens of degrees. This limitation implies that the aerial cannot distinguish between two point sources that fall within a single beamwidth.
Units of Measurement
A radio telescope can measure the angular position in the sky of a radio source, the angular size and the received intensity of the radiating source. The intensity of the source is called the ﬂux density and is a measure of power for a given range of wavelengths, per unit of surface area at the receiving telescope. The unit of ﬂux density is watt per square metre per unit frequency bandwidth (in Hertz) and is written as WmÀ2 HzÀ1. In honour of Karl Jansky, this standard unit is now called a Jansky (J). One Jansky is equivalent to 10À26 WmÀ2 HzÀ1. The strongest observed radio sources from space typically have ﬂux densities in the order of 1–100 J. In comparison, the signal from a mobile phone placed on the moon (a mobile phone has a transmission power of about 1 W at a frequency of 1.8 GHz) would produce a ﬂux density of about 1.45 J as measured on the earth’s surface. Thus, a mobile phone on the moon would produce an easily detected signal. Appendix A: What Is a Radio Telescope? 173
Fig. A.4 An example of a chart recording of the intensity of radio waves from the sun at a wavelength of 21 cm. In this example, the sun is moving through the aerial beam as the earth rotates. The Y-Axis shows the intensity of the received signal, and the X-axis is time marked in minute intervals. The intensity increases as the sun enters the aerial beam. In this instance, there is a strong source of radio emission produced above a sunspot group on the western side of the sun. The intensity increases markedly as the sun moves outside the aerial beam. In this example, the beamwidth of the aerial was about 3 arcmin. The diameter of the sun is 30 arcmin. The radio emission arises from the sun’s outer atmosphere: the diameter of the radio source is slightly larger than the optical size of the sun. The transit time of the radio sources is about two arcminutes (after Christiansen & Warburton, 1953)
A radio telescope can also measure the intensity of radio sources at different wavelengths (or frequencies). This procedure allows the astronomer to measure the radio spectrum of a source, intensity versus frequency. The radio spectrum of a radio source provides useful clues as to the nature of the physical process producing the radiation. Certain types of aerials which are responsive to broad ranges of frequencies, such as a rhombic aerial,1 are used when measuring multiple frequencies.
In an optical telescope, light is focused to a point so that the detector can be used to derive an image of the astronomical object. A radio telescope measures the intensity (ﬂux density) of the received radio waves from a given area of the sky. In early radio astronomy, this intensity was represented as a recording on a paper chart recorder (see Fig. A.4). The paper on the chart recorder was moved at a steady rate while the pen moved in response to changes in the intensity of the received signal as a function of time.
1A rhombic aerial uses one to three parallel wires suspended above the ground in a diamond shape, supported by poles or towers at each vertex to which the wires are attached by insulators. Each of the four sides are the same length, typically at least one wavelength or longer. 174 Appendix A: What Is a Radio Telescope?
Fig. A.5 An example of an early contour diagram showing the intensity of radio waves from the Galactic centre. This contour image was produced by scanning the aerial beam across the sky and recording the intensity observed in the parts of the sky that fell within the aerial beam (after Piddington & Minnett, 1951). Right ascension is the astronomical longitude coordinate, and declination is the astronomical latitude. The aerial beamwidth at 1210 MHz was 1.4
By measuring the intensity across different areas of the sky, it is possible to build a contour diagram of the intensity of the radio waves being received. The contour diagram is effectively an image of what the radio telescope is seeing. The higher the resolution of the telescope, the more detail can be produced in the image (see Fig. A.5).
Due to the physical size limitations and complexities of building large single-dish radio telescopes, radio engineers invented a technique to improve the resolution of a radio telescope without increasing the dish’s size. This technique relied on a method invented at the end of the nineteenth century by Albert A. Michelson, the “Michelson interferometer”. While principles of interferometry were well under- stood by optical astronomers such as Michelson, the technique was ﬁrst introduced into radio astronomy in 1946, based on the experiences of radar scientists during WWII. By using two aerials spaced at a distance and connected to a common receiver, the radio astronomers could achieve comparable angular resolution as a ﬁlled aperture telescope which was equivalent in size to the spacing between the indi- vidual aerials (see Fig. A.6). While not as sensitive as a ﬁlled aperture telescope, the same resolution was achieved at a much reduced complexity and cost. This type of radio telescope is referred to as an interferometer. The farther the spacing between Appendix A: What Is a Radio Telescope? 175
Fig. A.6 The radio waves arrive at the aerials at slightly different times. This phase difference creates a pattern of interference fringes in the combined signal. The spacing of the fringes is determined by the spacing between the aerials and produces a resolution equivalent to a ﬁlled aperture the same size as the spacing between the aerials
aerials, the higher the resolution achieved. The only limitation on resolution is the maximum spacing that can be used while still obtaining a very accurate measure- ment of the signal path distance between aerials so that signal phase can be accurately determined. In the early years of radio astronomy, this was difﬁcult for baselines longer than a few hundred metres. By the early 1950s, the use of radio- links helped overcome some of the limitations of physically connecting aerials. Later, with the invention of atomic clocks to synchronise measurements separately recorded, longer baseline instruments could be constructed. For example, the Very Long Baseline Array in the USA has a maximum baseline of 8000 km, comparable to the diameter of the earth (12,742 km). In the last few decades, both Japan and Russia have built spacecraft radio telescopes that have achieved baselines in the range 20,000–350,000 km. The resolutions achieved using these with earth-based baselines can far exceed that of the very largest optical telescopes, up to 0.3 milliarc seconds (the moon’s diameter of 30 arcmin is 1.8 million milliarcseconds in size). In a simple two-aerial interferometer, the radio wavefront arriving at each dish will have a slightly different time of arrival at each aerial causing a phase difference between the arriving signals. When the signals are in phase, they will constructively interfere and when they are exactly 180 out of phase they will destructively interfere producing an interference fringe pattern. The interference fringes are equivalent to having many small beams produced within the envelope of the beamwidth of a single aerial (see Fig. A.7). The resol- ution of the interferometer is a function of the fringe spacing; the larger the spacing, the narrower the fringe pattern and hence the higher the resolution.
In Australia, a technique of creating an interferometer using only a single aerial was developed in early 1946. This technique was based on experience gained with radar reﬂections from aircraft during WWII. By mounting the aerial on a cliff top 176 Appendix A: What Is a Radio Telescope?
Fig. A.7 The beam pattern of a single aerial is represented by the dotted line. For a small aerial, the beamwidth would be some tens of degrees. Where two identical small aerials are connected as an interferometer and separated by several hundred metres, the difference in the phase of the signals causes an interference pattern. This effect produces a pattern of interference fringes falling within the overall aerial beam pattern. Each fringe is equivalent to a narrower beamwidth beam of a few tens of arcminutes, enabling higher resolution measurements. The Y-axis is the sensitivity, and the x-axis is the displacement in angle on the sky
Fig. A.8 By observing both the direct radio waves from the source and the reﬂected ray from the sea, an interferometer using a single aerial was created. This system was equivalent to having two aerials spaced at a distance of twice the cliff height. At Dover Heights in Sydney’s eastern suburbs, the cliffs were 85 m in height Appendix A: What Is a Radio Telescope? 177 overlooking the sea and observing rising radio sources (ﬁrst the sun and later discrete radio sources) over the eastern horizon, an interferometer was created. The principle used interference from the direct radio radiation from the astronom- ical source with the waves reﬂected from the sea surface. This created an interfer- ometer with an equivalent spacing between aerials of twice the cliff height (85 m). A sketch of the sea-cliff interferometer is shown in Fig. A.8. Even though only a single aerial was required, numerous disadvantages were encountered. The baseline of the interferometer could not be varied. In addition, the low elevation of obser- vation implied that the refraction of the radio waves was substantial and variable from day to day, with resultant uncertain positional determinations. The Australian group did succeed in 1947 in ﬁnding higher cliff sites in New Zealand and were also able, for the ﬁrst time, to observe radio sources as they set in the west. Based on all these handicaps, within a few years the sea-cliff interferometer was discontinued, replaced by Michelson interferometers and arrays of antennas (see below).
The Mills Cross
Connecting a series of simple dipoles in a linear array produces a narrow beam; for example, a long east-west array produces a narrow E-W beam, a fan beam. If two linear arrays in the form of a cross are connected with the individual outputs combined, a narrow beam response is produced at the intersection of the two fan beams. The resolution is equivalent to that of a dish with the same diameter as the dimensions of the cross array (see Fig. A.9). This radio telescope was a cost- effective way of building a very large high-resolution radio telescope. The major limitation was the fact that the telescope could only be used at a single frequency, compared to the frequency agility of a single dish. In addition, the sensitivity was much less than that of a single dish of the same dimensions.
Fig. A.9 An illustration of a Mills Cross. The left diagram shows the arrangement of dipoles in each arm of the cross. The diagram on the right illustrates the aerial beam responses of the individual arms which are multiplied to produce a narrow pencil beam response. This system was the ﬁrst prototype cross built at Potts Hill in the western suburbs of Sydney. Each arm was 36.6 m in length and operated at 97 MHz (3 m wavelength) producing a pencil beam with a beamwidth of 8 (after Mills & Little, 1953). After the successful prototype, a cross with arms of 450 m was built at Fleurs ﬁeld station to the west of Sydney 178 Appendix A: What Is a Radio Telescope?
The Grating Array
By combining the signals received from a linear array of many small dish aerials, an aerial beam pattern consisting of a series of narrow fan beams (see Fig. A.10) can be produced. This radio telescope is analogous to an optical diffraction grating; thus, the grating array was created. The length of the array and spacing between the individual aerials determines the beamwidth of each fan beam. A crossed-grating array combines the features of the grating array with that of a Mills Cross, producing a series of intersecting fan beams that present a grid of high- resolution responses. This crossed-grating array was also sometimes referred to as a “Chris Cross” after its inventor, W.N. “Chris” Christiansen.
Fig. A.10 An example of a grating array using 32 aerials with a 217-m baseline (top). This conﬁguration produced an aerial response (bottom) as a series of fan beams with a 3 arcmin beamwidth and a spacing of 1.7 between beams. The Y-axis shows sensitivity with arbitrary units and X-axis the beam pattern in degrees (after Christiansen & Warburton, 1953) Appendix A: What Is a Radio Telescope? 179
Aperture Synthesis Telescope
An aperture synthesis telescope is a more complex type of interferometer, based on an array of telescopes, sometimes in a linear array, or in other conﬁgurations such as a T-shape or Y-shape. By combining the signals received at a variety of different possible spacings between individual telescopes, a high-resolution image can be reconstructed. The mathematical technique of the Fourier transform is used to reconstruct the image based on the sampled interference fringes. The technique also makes use of the rotation of the earth to achieve measurements over a period of time from a variety of different angles as the source moves across the sky. This combination results in an improved sampling of the interference fringes, leading to an improved image quality (see Fig. A.11). All modern synthesis radio telescopes make use of this technique. Martin Ryle received the Nobel Prize in Physics in 1974 for his perfection of the technique of aperture synthesis. The use of this technique for imaging became practical with the advent of digital computers to perform the Fourier transforms required to produce images. In 1955, Christiansen and Warburton produced a two-dimensional image of the quiet sun using the earth-rotational synthesis tech- nique. Nearly 6 months of manual calculations were required to produce a single image since a suitable digital computer was not available. For this reason, the Australian group did not pursue earth rotational synthesis until the several decades later.
Fig. A.11 An image produced in 1983 by the technique of aperture synthesis using the Karl G. Jansky Very Large Array of the National Radio Astronomy Observatory in New Mexico. The radio source is Cygnus A. The compact source at the centre is radio emission associated with a central black hole. The galaxy is at a distance of 600 million light years. The ﬁeld of view is 2.3 Â 1.3 arcmin, and the image has a resolution of 0.5 arcsec (courtesy of NRAO/AUI). The radio waves are coming from electrons propelled at nearly the speed of light through a long, thin “jet” at the core of the galaxy and deposited in giant “radio lobes” 180 Appendix A: What Is a Radio Telescope?
Christiansen, W. N., & Warburton, J. A. (1953). The distribution of radio brightness over the solar disk at a wavelength of 21 cm. Part 1 – A new highly directional aerial system. Australian Journal of Physics, 6, 190–202. Mills, B. Y., & Little, A. G. (1953). A high-resolution aerial system of a new type. Australian Journal of Physics, 6, 272–278. Piddington, J. H., & Minnett, H. C. (1951). Observations of Galactic radiation at frequencies of 1200 and 3000 Mc/s. Australian Journal of Scientiﬁc Research, 4, 459–475. Appendix B: Paul Wild: The Beer Disaster of November 1957
Paul enjoyed telling the story of Richard Twiss (1920–2005) from events in 1957. Richard Q. Twiss was a brilliant and eccentric UK astronomer who worked for a period at the CSIRO Division of Radiophysics in the 1950s. Later he joined Hanbury-Brown (1916–2002) at the University of Sydney, School of Physics in the 1960s, working on the Narrabri Stellar Intensity Interferometer; the eponymous Hanbury-Brown–Twiss effect from the mid-1950s is named after these two col- leagues. In Sydney, Twiss was universally respected; he was often characterised as a “caricature of an Englishman”. In 1957 during the week of 25 November, as was the usual habit, numerous colleagues from the Radiophysics Lab crossed the City Road at 5 pm to rush to the nearby public house (pub), the Lalla Rookh.2 The infamous 6 o’clock closing still existed; the scientists from the CSIRO labs and the Sydney University academics (men only) had to compete for accelerated service of beer with the New South Wales Government Railroad personnel from the nearby Redfern railyards. Each of the Radiophysics colleagues would take turns, as one by one would have their “shout” (for the non-Australians this meant to purchase drinks for all during the next “round”) before the dreaded closing. On this day, close to 6 pm, Paul Wild was to shout his mates; he returned with two hands overﬂowing with numerous glasses of beer. As he turned around, he bumped into a burly engine driver with coveralls. All the glasses spilled into the coveralls. Paul tells the story that the large victim looked him over as he was about to ﬂatten the startled scientist with his large ﬁsts. But, he looked at the fearful intended victim and began to laugh. At this point, Richard Q. Twiss appeared, the man to the rescue. In a very English upper-class accent, he said to the chastised Paul: “I say Wild, trouble with the natives?” All laughed; fortunately for Wild, the engine driver joined in.
2Apparently named after the last surviving full-blooded Tasmanian aboriginal, Truganni (circa 1812–1876). She was also known as Lalla Rookh.
© Springer International Publishing AG 2017 181 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 182 Appendix B: Paul Wild: The Beer Disaster of November 1957
This story was told time and time again in subsequent decades. Campbell Wade3 arrived at Radiophysics on 1 December 1957 from the USA by ship. He worked as a postdoc (recently a PhD from Harvard) with Joe Pawsey at the Potts Hill ﬁeld station, staying exactly 2 years before returning to the USA. Cam has reported, “In December 1957, nobody would talk about anything but that event....The partici- pants had expected the railroad personnel to tear the place apart...But everyone just went back to drinking as all laughed”. Almost 10 years later, Goss arrived in Sydney as a postdoctoral fellow at CSIRO. The despised 6 o’clock closing law had ended a few months earlier. A few days after arrival, Radhakrishnan (“Rad”) invited Goss to go across the street to the successor pub (the Lalla Rookh had been demolished) at 5 pm, now with a relaxed schedule. Goss was intimidated to be in the presence of famous radio astronomers: Wild, Steve Smerd, Kevin Sheridan, Norm Labrum, Rad, Max Komesaroff, etc. Within a few minutes as they sat down, the “natives” story was recounted by one of the other participants; the “new boy” had to hear the illustrious history of the Lalla Rookh. A year earlier in 1966 (20 April), Paul Wild had written Peter Scheuer at the Cavendish Laboratory in Cambridge.4 The main topic of the letter was to ask Scheuer’s opinion of a prospective predoctoral visit to Sydney from Cambridge. At the end of the letter, Paul concluded: The only other news of note is the strong rumour that the explosive expansion of Sydney University will cause its shock wave to demolish the Lalla Rookh within a month. So ends an era. There will be no more trouble with the natives. The “natives” story had a long life.
3Interview with Goss in Socorro, New Mexico, USA, on 11 January and 25 January 2007. Wade described an American’s ﬁrst impression of the Australian pub: “Good Australian fellowship, lots of drinking and everyone talking in a loud voice! The women had to go to the lounge bar where the beer was slightly more expensive”. 4From the Division of Radiophysics Archive (letters to Scheuer). Peter Scheuer was well known in Sydney since he had visited Radiophysics for three years starting in January 1960. In the letter, Paul also pointed out that Twiss had often referred in a joking manner to the “observationalists” at Radiophysics as the “idiots”. Appendix C: Supercomputing Cluster
In recent years, the CSIRO has named a line of supercomputers after prominent Australian Scientists in the CSIRO Division of Radiophysics whose pioneering work established the foundations of Australian Radio Astronomy. In July 2017, a new supercomputer cluster was commissioned by the CSIRO and named Bracewell as a way of honouring the scientiﬁc contributions made by Ron Bracewell during his career. The Bracewell cluster consists of 114 Dell PowerEdge C4130 rack mounted servers and is capable of performing 1 petaﬂops ﬂoating point operations per second. The cluster will be used for a variety of science projects that have high computation needs including radio astronomy, as well as providing machine learn- ing and deep learning software platforms that underpin the emerging data-intensive sciences. In 2014, the supercomputer centre in the Perth suburb of Kingston, Western Australia, supporting the Square Kilometre Array (SKA), was named the Pawsey Supercomputing Centre.5 This centre was appropriately named for J.L. “Joe” Pawsey, the “Grand Old Man of Australian Radio Astronomy” (see Chap. 2). Previous supercomputers have been named Ruby, after Ruby Payne-Scott, one of the original pioneers and the ﬁrst female radio astronomer (from 1944); Bowen, after Taffy Bowen who was chief of the Division from 1946 to 1971; and Pearcey after Trevor Pearcey, who designed and developed CSIRAC, Australia’s ﬁrst programmable digital computer, and one of the ﬁrst digital computers in the world.
5The Pawsey Supercomputing Centre is an unincorporated joint venture between CSIRO, Edith Cowan University, Murdoch University and the University of Western Australia.
© Springer International Publishing AG 2017 183 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 Appendix D: Time Line of Key Events
1926 Council of Scientiﬁc and Industrial Research (CSIR) established. 1939 Radiophysics Laboratory (RPL) established with D.F. Martyn as Chief of Radiophysics, P.V. Madsen Chair of Radiophysics Advisory Board and J.L. Pawsey hired into Radiophysics. 1942 F.W.G. White takes over as Chief of Radiophysics from Martyn and remains until 1945. 1942 B.Y. Mills joins RPL. 1943 R.N. Bracewell joins RPL to work with Pawsey until Bracewell goes to England in 1946 to complete his PhD. 1945 J.N. Briton becomes Chief of Radiophysics until 1946. Pawsey becomes leader of the team investigating sources of “thermal and Cosmic” noise marking the beginning of the Radio Astronomy group in Australia. The ﬁrst successful experiment in Australia occurred at sunrise on 3 October 1945 at Collaroy Plateau using one of the RAAF radars. 1946 E.G. “Taffy” Bowen takes over as Chief of Radiophysics, remaining as Chief until his retirement in 1971. The ﬁrst Australian paper on radio astronomy by Pawsey, McCready and Payne-Scott published in Nature. 1947 J.P. Wild joins RPL. 1948 W.N. Christiansen joins RPL. The November 1948 partial solar eclipse observations mark entry of Mills and Christiansen to radio astronomy. Penrith ﬁeld station established where Wild begins solar burst spectrum observations. 1949 CSIR reorganised into Commonwealth Scientiﬁc and Industrial Research Organisation (CSIRO). Bracewell returns from the UK to work at CSIRO (again). Mills and Thomas propose tentative source identiﬁcation of Cygnus A, which subsequently proves correct, but are dissuaded by R. Minkowski from publishing. 1950 Christiansen builds ﬁrst grating array telescope at Potts Hill. Wild proposes the classiﬁcation of solar radio bursts into three classes: Type I, II and III based on his work at Penrith.
© Springer International Publishing AG 2017 185 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 186 Appendix D: Time Line of Key Events
1951 Christiansen and J. Hindman conﬁrm detection of 21-cm Hydrogen line. 1952 International Union for Radio Science (URSI) meeting held in Sydney showcasing the achievements of Radiophysics. Mills proposes two-class distribution of discrete radio sources: one Galactic and the other isotopically distributed. This marks the beginning of controversy with Cambridge. 1953 Mills Cross prototype tested at Potts Hill; Fleurs ﬁeld station established and construction of Mills Cross begins; north-south array added to solar grating array at Potts Hill. 1954 Observations begin using Mills Cross at Fleurs. Wild establishes Dapto ﬁeld station. Pawsey elected Fellow of the Royal Society. Bracewell accepts lectureship to the University of California, Berkeley, from September 1954 to June 1955 at the invitation of Otto Struve. 1955 Radio Astronomy published by Pawsey and Bracewell. Bracewell moves to Stanford and joins Electrical Engineering faculty in December 1955. Christiansen publishes ﬁrst use of earth-rotational synthesis to produce 2-D image of the sun. 1957 Chris Cross built at Fleurs. 1959 18 m Kennedy Dish added to E-W arm of Chris Cross to become the Fleurs Compound Interferometer. In 1962, the Kennedy Dish moved to Parkes. 1960 Mills moves to Department of Physics and Christiansen to Department of Electrical Engineering, University of Sydney. 1960 Bracewell builds Stanford Microwave Spectroheliograph. 1961 Frater joins Dept. of Electrical Engineering, University of Sydney. 1961 Parkes 64 m Radio Telescope opens (also known as the Giant Radio Telescope GRT). 1962 Pawsey leaves Radiophysics for NRAO, dies 30 November 1962. Funding grant approved by National Science Foundation (NSF) to commence work on Molonglo Cross. Ford Foundation provides initial funding grant for Culgoora Radioheliograph. 1963 Fleurs ﬁeld station transferred to the University of Sydney; the Chris Cross would be the foundation for the development of the Fleurs Synthesis Telescope. Christiansen’s ﬁrst visit to China. Mills elected Fellow of the Royal Society. 1965 Molonglo Observatory opened by Prime Minister of Australia, Sir Robert Menzies on 19 November 1965. 1967 Molonglo Cross fully operational. Culgoora radioheliograph operational. 1969 Radiotelescopes by Christiansen and Hogbom€ published. 1970 Westerbork Array opens in the Netherlands. Wild elected Fellow of the Royal Society. 1971 Wild takes over from Bowen as Chief of Radiophysics. 1973 Fleurs Synthesis Telescope begins limited observations and continues to be developed throughout 1970s. 1976 Mills appointed Companion in the Order of Australia. Appendix D: Time Line of Key Events 187
1978 Molonglo Observatory transitions to Molonglo Observatory Synthesis Telescope (MOST). Wild appointed Chairman of CSIRO until his retirement in 1985. Minnett appointed Chief of Radiophysics. Christiansen becomes President of URSI until 1981. Wild appointed Commander of the Order of the British Empire (CBE). 1979 Bracewell retires. Christiansen retires. 1981 R.H. Frater becomes Chief of Radiophysics following the retirement of Minnett. 1984 Culgoora Solar Observatory closed. 1985 Wild retires from CSIRO. Mills retires. 1986 Wild appointed Companion of the Order of Australia. 1988 Australia Telescope opened by the Prime Minister of Australia, Hon. Bob Hawk. Fleurs Synthesis Telescope closed down. 2017 UTMOST opened, the University of Swinburne modiﬁcation of the Molonglo Observatory Synthesis Telescope (MOST) for fast radio burst (FRB) survey. Appendix E: Dramatis Personae for Four Pillars of Radio Astronomy
Bok, Bart (1906–1983) Dutch-American astronomer whose primary research interest was the structure of the Milky Way; career was at Harvard, Mt Stromlo (Canberra, Australia) and the University of Arizona Bolton, John (1922–1993) British-Australian astronomer who identiﬁed ﬁrst known radio galaxies together with Gordon Stanley and Bruce Slee. He established Owens Valley Observatory in California and was later the ﬁrst Director of the Parkes Radio Telescope in Australia Bowen, Edward G. “Taffy” (1911–1991), British born in Wales, member of the group headed by Sir Robert Watson Watt who developed British radar in 1935; member of Tizard Mission from the UK to the USA in 1940; Radiation Laboratory Massachusetts Institute of Technology until 1943; CSIR and later CSIRO Division of Radiophysics from 1944; Chief of Division of Radiophysics from 1946 to 1971 Ewen, Harold Irving “Doc” (1921–2015) American; at Harvard University in 1951, he and Edward Purcell carried out the ﬁrst detection of the Hydrogen line at 21 cm; later was President of the Ewen Knight Corporation and the Ewen Dae Corporation Faraday, Michael (1791–1867) British; established the concept of the electro- magnetic ﬁeld and showed that magnetism could affect rays of light Hanbury-Brown, Robert (1916–2002) British astronomer and physicist born in India, made notable contributions to the development of radar during WWII and the creation of intensity interferometers; University of Manchester and University of Sydney Herschel, William (1738–1822) British astronomer born in Germany, discov- ered infrared radiation in sunlight Hertz, Heinrich (1857–1894) German, physicist who proved the existence of electromagnetic waves and for whom the unit of frequency—cycles per second—is named Hey, James Stanley (1909–2000) British physicist who detected radio emis- sions from sunspots while doing radar research during WWII; worked for the Army Operational Research Group and the Royal Radar Establishment at Malvern
© Springer International Publishing AG 2017 189 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 190 Appendix E: Dramatis Personae for Four Pillars of Radio Astronomy
Hindman, J.V. (1919–1999) Australian radio astronomer who worked with Christiansen on the conﬁrmation detection of the Hydrogen line and the initial H-line survey. He continued work on H-line surveys later at Parkes and then moved to the Australian National University, Siding Spring Observatory in 1967 Hogbom,€ Jan (1929–) Swedish astronomer who developed the CLEAN algo- rithm for processing images made with radio telescopes; played a major role in the design of the Westerbork Synthesis Radio Telescope in the Netherlands Hoyle, Fred (1915–2001) British astronomer known for his proposal (along with Gold and Bondi) of the Steady-State theory of the universe; major work was the theory of stellar nucleosynthesis; Cambridge University Jansky, Karl Guthe (1905–1950) American physicist and engineer who ﬁrst discovered radio waves arising from the Milky Way; Bell Labs Labrum, Norm R. (1921–2011) Born in England and moved to Australia in 1946 taking a position in the CSIRO Division of Radiophysics. He worked in solar radio astronomy and together with Don McLean co-edited the book Solar Radiophysics [McLean, D.J., and Labrum, N. (eds.), 1985. Cambridge, Cambridge University Press] Laby, Thomas Howell (1880–1946) Australian Professor of Natural Philosophy at the University of Melbourne Little, Alec (1925–1985) Australian radio astronomer who worked with Ruby Payne-Scottt and Mills on instrument development and observations and later directed Molonglo Radio Observatory Lovell, A.C. Bernard (1913–2012) British, Professor University of Manchester, Founder of the Jodrell Bank Observatory; during WWII, he was a prominent scientist in UK radar research, playing a major role in the development of the aircraft mounted H2S navigational system at 11 cm; the higher frequency version H2X could be used as a radar bombsite; after the war, the Jodrell Bank Observatory became a prominent research institution; the 250 foot telescope (now the Lovell Telescope) became operational in 1957; Lovell became a well-known public ﬁgure in the UK as a spokesman for science policy Madsen, John P.V. (1879–1969) Australian, Professor of Electrical Engineer- ing, University of Adelaide; founder of the Radio Research Board Martyn, David Forbes (1906–1970) Scottish-Australian; leading CSIR (O) ionospheric scientist; ﬁrst chief of CSIR’s Radiophysics Laboratory Maxwell, James Clerk (1831–1879) Scottish physicist; formulated the theory of electromagnetic radiation McCready, Lindsay (1910–1976) Australian astronomer and engineer who specialised in receiver systems; worked with Ruby Payne-Scott in 1945–1951 Messel, Harry (1922–2015) Canadian-born Australian physicist and educator; Head of the School of Physics, University of Sydney Minkowski, Rudolph (1895–1976) German-born American astronomer who studied supernovae and with Walter Baade made the ﬁrst identiﬁcation of the strong radio source Cygnus-A with a faint galaxy in 1954 using the 200 in telescope; Mount Wilson and Palomar Observatory in California Appendix E: Dramatis Personae for Four Pillars of Radio Astronomy 191
Minnett, Harry (1917–2003) Australian engineer who guided the design of the Parkes Radio Telescope; later Chief of CSIRO Division of Radiophysics, 1978–1981 Oort, Jan (1900–1992) Dutch astronomer; one of the discoverers of the rotation of the Milky Way in the late 1920s and in 1950 the “Oort Cloud” of distant comets in the solar system at distances of 100,000 times to the earth–sun distance; founder of radio astronomer in the Netherlands after WWII O’Sullivan, John (1947–) Australian electrical engineer; Netherlands Founda- tion for Radio Astronomy, then CSIRO Division of Radiophysics; member of the group that invented Wi-Fi at CSIRO Payne-Scott, Ruby (1912–1981) Australian, radar researcher at CSIR Division of Radiophysics during WWII; ﬁrst woman radio astronomer, March 1944 obser- vations made at 11 cm wavelength; discoverer of Type I and Type III solar bursts during the post-war rebirth of radio astronomy in Sydney; co-discoverer of Type II bursts (along with Yabsley and Bolton) in March 1947; left CSIRO in 1951 at the birth of her son, the prominent mathematician, Peter G. Hall (FRS 1951–2016) Penzias, Arno (1933–) German-born American physicist, radio astronomer Nobel Prize in Physics 1978 with Robert W. Wilson for the discovery of the cosmic microwave background; Bell Labs Purcell, E.M. (1912–1997) American physicist; along with Doc Ewen involved in detection of the 21 cm line of neutral hydrogen in 1951; Nobel Prize in Physics (1951) along with Felix Bloch for the discovery of nuclear magnetic resonance Ratcliffe, John A. “Jack” (1906–1987) British radio physicist at the Cavendish Laboratory at the University of Cambridge UK; pioneering research on the iono- sphere; during WWII prominent radar scientist at the Telecommunications Research Establishment in the UK; major role in the initiation of radio astronomy at Cambridge in the post-war years; thesis advisor of Pawsey and Bracewell Reber, Grote (1911–2002) American electrical engineer; the second radio astronomer following Karl Jansky; he built his own 31 foot (9 m) radio telescope, conducting the ﬁrst systematic radio sky survey; moved to Tasmania Australia in 1954 to work on low-frequency radio astronomy remaining until his death Rivett, David (1885–1961) Australian chemist and science administrator, a major contributor to Australian science in the ﬁrst half of the twentieth century; Chief Executive Ofﬁcer of the newly formed CSIR (Council for Scientiﬁc and Industrial Research) from 1927 to 1946; played a major role in the formation of the Division of Radiophysics in 1939, as well as the administration of the radar research programme in WWII; from 1946 to 1949, he was Chairman of CSIR; retired in 1949 as the new Commonwealth Scientiﬁc and Industrial Research Organisation (CSIRO) was formed in May 1949 Ryle, Martin (1918–1984) British radio astronomer at Cambridge; for the development of radio astronomical aperture synthesis, he was awarded the Nobel Prize in Physics in 1974 (shared with Anthony Hewish); Ryle, Pawsey and Lovell were the ﬁrst three radio astronomers to become Fellows of the Royal Society of London 192 Appendix E: Dramatis Personae for Four Pillars of Radio Astronomy
Shain, C. Alex (1922–1960) Australian; low-frequency research at CSIRO at the ﬁeld stations at the Hornsby and Fleurs Slee, Bruce (1924–2016) Australian radio astronomer; important contributions to solar system, Galactic and extragalactic astronomy while working at CSIRO; he had detected the sun in late 1945 or early 1946 while a member of the Royal Australian Air Force using an aircraft warning radar antenna located near Darwin Southworth, George C. (1890–1972) American engineer at Bell Labs known for developing radio frequency wave guides; he carried out the ﬁrst high-frequency observations of the sun during WWII, published in 1945 Struve, Otto (1897–1963) Russian-born American astronomer; directed Yerkes Observatory of the University of Chicago at Williams Bay, Wisconsin; founding director of the McDonald Observatory near Fort Davis, Texas; served as the ﬁrst director of the National Radio Astronomy Observatory from 1959 to 1962 Swarup, Govind (1929–) Indian radio astronomer; PhD at Stanford University with Bracewell in late 1960; founder of the radio astronomy group at the Tata Institute of Fundamental Research in Bombay; a leader in the design and imple- mentation of the Giant Metrewave Radio Telescope van de Hulst, Hendrik (1918–2000) Dutch astronomer; during the last year of WWII, he predicted the existence of the 21 cm hyperﬁne line of atomic hydrogen; leader in early radio astronomy in the Netherlands; major leader in the formation of astronomical research from space in Europe; University of Leiden Warburton, J.A. (1924–2005) Australian; participated with Christiansen on construction and utilisation of the Solar Grating Array at Potts Hill before moving to work in Cloud Physics in 1957 White, Frederick William George (1905–1994) New Zealand-born iono- spheric physicist who became the second Chief of the CSIR Division of Radiophysics in 1942, serving until 1944; then a member of the CSIR Executive; in 1949, he became the Chief Executive Ofﬁcer; in 1959 when Sir Ian Clunies Ross (Chairman from 1949 to 1959) died, White became Chairman, serving until 1970 Wilson, Robert W. (1936–) American astronomer at Bell Labs and the Harvard- Smithsonian Center for Astrophysics; Nobel Prize in Physics in 1978 along with Arno Penzias for the discovery of the cosmic microwave background Yabsley, Don E. (1923–2003) Astronomer with CSIRO; worked on radar during WWII; early solar research at Georges Heights, Sydney; he worked on the new Parkes Radio Telescope in the 1960s perfecting methods of determining the accurate shape of the antenna; later he played a major role in the design of the Australia Telescope in the 1980s Zwicky, Fritz (1898–1974) Swiss-American astronomer; an iconoclast scientist who inferred the existence of dark matter based on observations of the velocity dispersion of individual objects in clusters of galaxies; based on his experience in observing supernovae with Walter Baade in the 1930s (the term “supernova” was coined by these two in 1934), Zwicky proposed that supernovae resulted from the transition of normal stars to neutron stars; he was a Caltech professor. Appendix F: Abbreviations
AC Companion of the Order of Australia AST Australian Synthesis Telescope ASTRON The Netherlands Institute for Radio Astronomy AT Australia Telescope ATCA Australia Telescope Compact Array ATNF Australia Telescope National Facility AWA Amalgamated Wireless (Australasia) Ltd BOMAS Bottom Mapping Sonar CBE Commander of the Most Excellent Order of the British Empire CCIR International Radio Consultative Committee CMB Cosmic Microwave Background CMOS Complementary Metal-Oxide-Semiconductor CSIR Council for Scientiﬁc and Industrial Research (Australia) 1926–1949 after which it became CSIRO CSIRO Commonwealth Scientiﬁc and Industrial Research Organisation (Australia) FFT Fast Fourier Transform FST Fleurs Synthesis Telescope GRT Giant Radio Telescope—The working name for the Australian project that led to the 64 m Parkes Radio Telescope IAU International Astronomical Union ICAO International Civil Aviation Organization ICSU International Council for Science IEEE Institute of Electrical and Electronics Engineers ILS Instrument Landing System K Kelvin—the primary unit of temperature based on an absolute scale. The temperature increment is the same as Celsius. Absolute zero (O K) is À273.15 C MGPS-2 Molonglo Galactic Plan Survey—No. 2 MOST Molonglo Observatory Synthesis Telescope
© Springer International Publishing AG 2017 193 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 194 Appendix F: Abbreviations
MSH Abbreviation for the Mills, Slee and Hill survey that catalogued over 2000 discrete radio sources between 1954 and 1957 NRAO National Radio Astronomy Observatory (USA) NSF National Science Foundation (USA) OTC Overseas Telecommunications Corporation (Australia) PLANS Program for Local Area Network Systems PPI Plan Position Indicator—a radar display of azimuth and range RAAF Royal Australian Air Force RPL Radiophysics Laboratory (CSIRO Australia) SKA Square Kilometre Array SKAMP Square Kilometre Array Molonglo Prototype SNR Supernova remnant SUMSS Sydney University Molonglo Sky Survey TGV TGV is France’s intercity high-speed rail service (Train a Grande Vitesse) URSI Union Radio-Scientiﬁque Internationale—International Union of Radio Science VFT Very Fast Train VLSI Very-Large-Scale Integration VOR Very-High-Frequency (VHF) Omnidirectional Range WST Westerbork Synthesis (radio) Telescope Index
A Centaurus A (work with), 142 Aitchison, Ronald E. (“Ron”), 49, 156 Conklin, E.K., 142, 148 Amalgamated Wireless Australia (AWA), 46, controversy over Nature article, 143 62, 156 CSIRO (work at), 134–137 Anglo Australian Telescope, 47, 82, 125 D-layer ionisation, 133 Atkinson, Sally, xiii, 143 early life, 131–133 Austek Microsystems, 162–163 education, 132–134 Australian Synthesis Telescope, 49, 156 extra-terrestrial intelligence, 148 Australian Telescope Compact Array (ATCA) Fourier transforms, vii–viii, 20, 33, 65, 72f, of CSIRO Astronomy and Space 134–135, 137, 137n, 138, 144, 148, Science (CASS), vii, 78, 82, 84, 123, 162–163, 163f, 165, 179 157, 159 Hartley transforms, 148 Australia Telescope National Facility (ATNF), Heliopolis, 139, 141–142, 142f, 143f, 145f xiii, 158, 164 honours and awards, 147–148 Australia Telescope of CSIRO Astronomy important papers, 137–138 and Space Science (CASS), xiii, 49, 78, ionomers, 134 87, 123, 128, 155, 157–158, 158f, 159, projection-slice theorem, 138 159f, 160f, 161f, 162f, 163–164, Stanford (work at), 139–148 187, 192 Stanford Microwave Spectroheliograph, 139, 140f, 141f, 142f, 149f, 186 studying with J.A. Ratcliffe, 133–134 B sundials, vx, 1, 3f, 4f, 148, 149f Badgerys Creek, 27, 28f, 29f, 32, 34 Swarup, Govind, 65, 87, 139, 140f, 141, Beam Wireless System, 62 141f, 153, 192 Benelux Cross, 73, 153 trees, 148 Big Bang vs Steady State, xi, 35n, 36, 37n, 38, URSI lapel pin, 134, 136f 43, 168, 190 Burke, Bernard F., 154, 155f Bolton, John Gatenby, 18, 19n, 20, 25–26, 32f, 82, 93, 104, 105f, 106, 125f, 189, 191 Bowen, Edward G. (“Taffy”), 3, 14–15, 18, C 18f, 25, 33, 42, 44f, 45, 62, 82, 116–117, Cambridge 2C survey, 36, 38, 43f 143, 157f, 165, 183, 185–186, 189 Cambridge 3C survey, 38 Bracewell, Ronald Newbold (“Ron”) Chris Cross, viii, xi, 41f, 70, 75f, 76, 76f, 77, applications for medical imaging, viii, xii, 77f, 78f, 79f, 80f, 81f, 82f, 83f, 88, 108, 143, 153, 162, 165, 168 178, 186
© Springer International Publishing AG 2017 195 R.H. Frater et al., Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell, Astronomers’ Universe, DOI 10.1007/978-3-319-65599-4 196 Index
Christiansen, Wilbur Norman (“Chris”) CSIRO. See Commonwealth Scientiﬁc and China, 85–86, 86f, 87, 186 Industrial Research Organisation Chris Cross, viii, xi, 41f, 70, 75f, 76, 76f, (CSIRO) 77, 77f, 78f, 79f, 80f, 81f, 82f, 83f, 88, Culgoora, 108, 110f, 113f, 114f, 116f, 118f, 108, 178, 186 119f, 120f, 158, 159f, 165, 187 development of grating array, 65–67, 68f, Culgoora Radioheliograph, 42, 109f, 110f, 69f, 70f, 71f, 72f, 73f, 74f, 75f, 88, 178, 111f, 114f, 116f, 118f, 119f, 120f, 121f, 185–186, 192 156, 186 early life, 59–62 early projects, 62 education, 60–62 D ﬁrst use of earth-rotational synthesis, Dapto, 93, 96f, 97, 97f, 98f, 99, 99f, 100f, 102f, 65, 168 103f, 105f, 106f, 107f, 126, 186 Fleurs Synthesis telescope, 76–80, 82–83, Discrete radio sources, xi, 1, 4f, 19, 25n, 26–31, 83f, 84, 87–88, 155, 159, 186–187 36, 38–40, 54, 138, 168, 177, 186 grating array at Potts Hill, 65–67, 68f, 69f, 70f, 71f, 72f, 73f, 74f, 75f, 88, 178, 185–186, 192 E Hogbom,€ Jan A., Benelux Cross (work Earth-rotational synthesis, xi, 65, 72f, 73, 76, with), 73, 153 88, 153, 155, 155n, 168, 179, 186 hole in the ground spherical reﬂecting Ekers, R.D. (“Ron”), ix, xi–xii, 143, 158, 159n, telescope, 73, 172f 160 honours and awards, 86 Electromagnetic spectrum, 7–9 hydrogen line work with J.V. Hindman, Ewen, Harold I. (“Doc”) and Purcell, Edward 67–70, 74f, 88, 186, 190 M., 32f, 67–68, 103, 189, 191 Labor Club, 60–61 limb brightening discoveries, viii, 65, 72f marriage to Elspeth Hill, 61 F Meudon Observatory, France (work at), 70 Faraday, Michael, 7, 189 Radiotelescopes book, vii, 73, 154, 186 Fleurs ﬁeld station, 34, 35f, 36f, 37f, 38f, 39, roles in scientiﬁc unions, 86 41f, 45, 71, 75, 75f, 76, 76f, 77, 78, 78f, RPL, 62, 70 81f, 82, 82f, 84f, 85, 87–89, 136f, 155, solar research at Potts Hill, 63f, 64, 64f, 65, 177f, 186, 192 66f, 68f, 69f, 71f, 73f, 74f, 75f, 88–89, Fleurs Synthesis telescope, 76–80, 82, 83, 83f, 139n, 185–186, 192 84, 87–88, 155, 159, 163, 186–187 Swarup, Govind, 65, 87 Fourier transform, 163f, 165, 179, vii–viii, 20, University of Sydney, viii, 72–88 33, 65, 72f, 134–135, 137, 137n, 138, Vela Pulsar, 82 144, 148, 162–163 Cliff-top interferometer, 25, 175, 176f Frater, Robert H. (“Bob”), vii–viii, xi, xiif, xiii, Cloud Physics, 17, 20, 116–117, 192 xvf, 46–47, 49, 61, 68–69, 79–80, 85, Commonwealth Scientiﬁc and Industrial 87n, 111, 123, 128, 156–157, 156f, Research Organisation (CSIRO), 157, 157f, 158f, 159, 160f, 162–164, vii–viii, xii–xiii, xiif 3, 10, 17, 17f, 18, 186–187 23–24, 27, 38f, 45, 49, 62, 71–72, 75–77, 85n, 87, 108, 116, 120, 123, 128f, 129, 133–134, 139, 149, 155–157, H 157f, 158, 160f, 162, 164, 167, Hanbury Brown, Robert, 30, 32f, 45, 116, 156, 181–183, 185, 187, 189–192 181, 189 Conklin, E.K., 142, 148 Hawking, Stephen W., 160 Cosmic microwave background (CMB), 39, Height ﬁnding radar, 24 142, 191–192 Herschel, William, 7–8, 189 Council for Scientiﬁc and Industrial Research Hertz, Heinrich, 8, 12, 147, 189 (CSIR), 3, 12–15, 17–18, 24, 62, 93, Hey, James Stanley, 12, 189 116, 167, 185, 189–192 Hill, Elspeth, 61, 87 Index 197
Hogbom,€ Jan A., vii, 73, 153–154, 186, 190 Mills Cross prototype, 33–34, 34f, 177f 186 Hoyle, Sir Fred, 35, 35n, 36, 190 Molonglo, 43, 46, 47, 47f, 48, 48f, 49f, 50f, Hull, Elaine, 93 51–52, 54–55, 80, 82, 84, 155–157, Hydrogen Line research, viii, 20, 25, 67, 69, 74f, 186–187, 190 88, 103–104, 106, 186, 189, 190–192 MOST, 49, 51–52, 52f, 53, 53f, 155n, 187 MSH survey, 39–40, 48 One Mile Cross, 42, 45, 51 I Physics, University of Sydney, viii, 23, 43, Interscan system, 118–119, 126f, 157, 164 45, 48f, 186 Ionomers, 134 Potts Hill (work at), 26, 26f, 27, 33–34, 34f, Ionospheric scintillation, 99, 101 177, 186 produces “radio pictures” for ﬁrst time, 30 swept-lobe interferometer, 25–26, 26f, 27 J tuberculosis, 25 Jansky, Karl G., 6, 9–10, 10f, 170, 172, 190–1 Mills Cross, viii, xi, 27, 32–34, 34f, 35, 35f, Jansky Karl G., Very Large Array, iv, xv, 1, 3f, 36f, 37f, 38f, 39, 39f, 40f, 41f, 42, 42f, 154, 179f 43, 45, 54, 71, 75f, 81f, 82f, 83f, 88, Jupiter, 154, 155f 136f, 154, 156, 168, 177–178, 186 Mills-Slee-Hill (MSH) survey, 39–40, 48 Minkowski, Rudolph, 26, 185, 190 K Molonglo Observatory Synthesis Telescope Karmalsky, Lerida, 23 (MOST), 49, 51–52, 52f, 53, 53f, Kerr, Frank J., 4, 5n, 15f, 20, 32f, 42n 155n, 187 Molonglo Radio Observatory, 47–48, 48f, 186–187, 190 L Molonglo Reference Catalogue, 47 Little, Alec G., 25, 32f, 33–34, 38f, 46, 48–49, MOST. See Molonglo Observatory Synthesis 51, 63f, 135, 139, 156, 177, 190 Telescope (MOST) Murray, John D., 96, 96f
M Madsen, John P.V., 12–14, 14f, 185, 190 N Martyn, David Forbes, 13–14, 65, 185, 190 Narrabri, 45, 78, 108, 109f, 123, 156, 181 Maxwell, James Clerk, 8, 25, 190 National Science Foundation (NSF), 45, 186 McCready, Lindsay L., 20, 25n, 42n, 44f, 62, Nature, 19, 30, 82, 101, 143, 185 93–94, 185, 190 Messel, Harry, 43, 45–46, 48f, 55, 190 Mills, Bernard Yarnton (“Bernie”) O Badgerys Creek (work at), 27, 28f, 29f, One Mile Cross, 42, 45, 51 32, 34 Optical-Stellar Interferometer, 156, 181 Communist Party, 23 O’Sullivan, John D., viii, xiii, 87, 159, 159n, controversy with Cambridge and Ryle, 30, 160, 162–163, 163f, 164f, 191 35, 39, 186 Overseas Telecommunication (OTC), 46, 62, developing the phase switch, 27, 32–33 156, 159 early life, 23 Owens Valley Radio Observatory, 20, early projects, 24–25 104–105, 189 education, 23 funding from NSF, 45, 186 identiﬁcation of discrete sources, 25–31 P Labor Club, 23 Parkes radio telescope, 18f, 20, 42, 44f, 45, 48, Lewis, Crys, xiii, 54 72, 75, 108, 123, 124f, 125f, 142–143, Log(N) vs Log(S), 29, 36 156, 158, 186, 189–193 Mills Cross at Fleurs, 34, 35f, 36f, 37f, 38f, Pawsey, Joseph Lade (“Joe”), vii, xi–xiii, xv, 1, 39, 39f, 40f, 41f, 42, 42f, 45, 54, 81f, 3–5, 5f, 13, 15f, 17–18, 19f, 20, 20n, 82f, 83f, 136f, 186 24–25, 25n, 27, 33, 38f, 42–43, 62–63, 198 Index
65, 67, 73f, 75–76, 88n, 93, 105f, 108, Solar burst types, xi, 94, 94f, 102f, 107f, 111, 116, 133, 137–138, 139n, 141f, 155, 111n, 168 165, 182–183, 185–186, 191 Solar eclipse research, 25, 64, 64f, 65, 66f, Payne-Scott, Ruby V., 20, 25, 32f, 62, 63f, 183, 98, 185 185, 190–191 Southworth, George C., 12, 192 Penrith Station, 93, 94f, 95f, 100f, 185 Square Kilometre Array Molonglo Pathﬁnder Penzias, Arno A., 39, 142, 191–192 (SKAMP), 53 Potts Hill, 26, 26f, 27, 33–34, 34f, 63f, 64, 64f, 65, Stanford Microwave Spectroheliograph, 139, 66f, 68f, 69f, 71, 71f, 73f, 74f, 75f, 88–89, 140f, 141f, 142f, 149f, 186 135, 139n, 177f, 182, 185–186, 192 Stanford University, vii–viii, xv, 137, 140f, Power-law spectrum, 102 153, 186, 192 “Present Difﬁculties in Australian Radio Steady State theory, xi, 35n, 36, 168, 190 Astronomy,” 75 Sullivan, Woodroof T., III, xiii, xv, 1, 8n, 27n, Program for Local Area Network Systems 30, 38, 42n, 88n, 97–98, 112, 137–138, (PLANS), 163 148, 153n, 165 SUMSS. See Sydney University Molonglo Sky Survey (SUMSS) R Sunspots, 65, 66f, 88n, 99, 113n, 189 Radar research, vii, 3, 12–16, 24, 64, 92–93, Swarup, Govind, 65, 87, 139, 140f, 141, 141f, 116, 133, 189–192 153, 192 Radiata, 87, 164 Swept-lobe interferometer, 25, 25n, 26, 26f, 27, Radioheliograph at Culgoora, 42, 108, 109f, 103f 110f, 111, 111f, 112f, 113f, 114, 114f, Sydney University Molonglo Sky Survey 115f, 116f, 117f, 119f, 121f, 122f, 123, (SUMSS), 53 123f, 128, 156, 186 Radiophysics Laboratory (RPL), xiii, 3, 12–13, 14f, 15f, 24, 70, 93, 116, 133, 165, 167, T 185, 189–191 Tomography, viii, 138, 143–144, 146–147, 165 Radio stars, 20, 29, 31, 36 Radio Sundial, iv, xv, 1, 3f, 4f, 148, 149f Radiotelescopes (book), vii, 73, 154, 186 U Ratcliffe, John A. (“Jack”), 13, 133–134, 135f, Upgraded Molonglo Observatory Synthesis 138, 191 Telescope (UTMOST), 54 Reber, Grote, 10–11, 11f, 12, 41f, 171, 191 Ritter, Johann, 7–8 Rivett, Sir A.C. David, 3, 14–15, 15n, 17–18, V 62–63, 191 van de Hulst, Hendrik, 25, 67, 192 Roberts, James Alfred (“Jim”), 99, 101–102, Vela Pulsar, 47, 51f, 82 105f, 126, 137 Very Large Array (VLA) (National Radio Rowe, William, 96 Astronomy Observatory), iv, xv, 1, 3f, RPL. See Radiophysics Laboratory (RPL) 147, 154, 179f Ryle, Sir Martin, xi, 27, 30–31, 35–38, 43f, 73, 141, 154, 168, 179, 191 W Westerbork Synthesis Telescope, 73, 87, 154, S 160, 186, 190 Shain, Charles, Alexander (“Alex”), 20, 32f, White, Frederick William George, 13–15, 17f, 38f, 81f, 192 18, 74f, 116, 167, 185, 192 Signal and Imaging Technology Group, 162 Wi-Fi, viii, xii, 153, 156, 159, 162–164, 167, SKAMP. See Square Kilometre Array 191 Molonglo Pathﬁnder (SKAMP) Wild, John Paul Slee, O. Bruce, 19, 19n, 25n, 32f, 35, 38, 38f, Anglo-Australian Telescope Board, 125 39, 40f, 64, 134–135, 189, 192 Astronomical Society of Australia, 115 Index 199
Chairman of CSIRO, vii–viii, 120–123, radioheliograph at Culgoora, 42, 108, 109f, 128f, 157f, 187 110f, 111, 111f, 112f, 113f, 114, 114f, Chief of RPL, 116, 186 115f, 116f, 117f, 119f, 121f, 122f, 123, Dapto rhombic antenna research, 97, 97f, 123f, 128, 156, 186 98f, 103f, 106f, 107f restructuring at CSIRO, 121 early life, 91 Shishov, V.I., 102 education, 92 Solar burst types, xi, 94, 94f, 102f, 107f, Gochelashvily, 102 111, 111n, 168 gravitational theory, 124 war time activities, 93 Haddock, Margaret, 129 work at RPL, 93 honours and awards, 129 work with solar ﬂares, 99 Hull, Elaine, 93 Zeeman effect, 103–104, 106, 108 hydrogen line, viii, 103–104, 106 Wilkes, Maurice V., 13 Interscan system, 118–119, 126f, 157, 164 Wilson, Robert W., 39, 142, 191–192 ionospheric scintillation, 99, 101 McCready, L.L. (work with), 93–94, 190 Penrith Station, 93, 94f, 95f, 185 Z power-law spectrum, 102 Zeeman effect, 103–104, 106, 108