Short History of Radio Astronomy Jansky – January 1932

Total Page：16

File Type：pdf, Size：1020Kb

Short History of Radio Astronomy Jansky – January 1932 Modiﬁed Bruce Array: Harald Friis design December 1932 Jansky’s 1932 Data Grote Reber- 1937 9.5 m Parabolic Reﬂector! Strip Chart output From Strip Chart to Contour Plot… 1940 Ap. J. paper…barely Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Jan Oort & Hendrik van de Hulst Lieden Observatory 1944 Predicted HI Line Detection of Hydrogen Line …… Ewen & Purcell 21 cm HI Line (1420 MHz) Purcell HI Receiver: Doc Ewen (1951) Milky Way in Optical Origin of SETI Nature, 1959 Philip Morrison 1959 Project Ozma: April 6, 1960 Tau Ceti & Epsilon Eridani Cosmic Background: Penzias & Wilson 1965 • 20 ft Echo Horn (Sugar Scoop): • Harald Friis design Pulsars: Bell and Hewish 1967 Detection of Pulsars: ~100ft of chart/day Chart recording of the pulsar Examples of scintillating detection and an interference signal somewhat later in time. Fast chart recording of pulsar emission (LGM nomenclature is “Little Green Arecibo Message: 1974 Big Ear Radio Telescope OSU Wow! Signal, Aug. 15, 1977 Sagitarius, Chi Sagittari star group NRAO 36ft Kitt Peak Telescope The Drake Equation The Drake equation states that: where: N = the number of civilizations in our galaxy with which communication might be possible; and R* = the average rate of star formation per year in our galaxy fp = the fraction of those stars that have planets ne = the average number of planets that can potentially support life per star that has planets fℓ = the fraction of the above that actually go on to develop life at some point fi = the fraction of the above that actually go on to develop intelligent life fc = the fraction of civilizations that develop a technology and desire to communicate. L = the length of time for which such civilizations release detectable signals into space .

Copy Link

Recommended publications

History of Radio Astronomy
History of Radio Astronomy Reading for High School Students Getsemary Báez Introduction form of radiation involved (soon known as electro- Radio Astronomy, a field that has strongly magnetic waves). Nevertheless, it was Oliver Heavi- evolved since the end of World War II, has become side who in conjunction with Willard Gibbs in 1884 one of the most important tools of astronomical ob- modified the equations and put them into modern servations. Radio astronomy has been responsible for vector notation. a great part of our understanding of the universe, its A few years later, Heinrich Hertz (1857- formation, composition, interactions, and even pre- 1894) demonstrated the existence of electromagnetic dictions about its future path. This article intends to waves by constructing a device that had the ability to inform the public about the history of radio astron- transmit and receive electromagnetic waves of about omy, its evolution, connection with solar studies, and 5m wavelength. This was actually the first radio the contribution the STEREO/WAVES instrument on wave transmitter, which is what we call today an LC the STEREO spacecraft will have on the study of oscillator. Just like Maxwell’s theory predicted, the this field. waves were polarized. The radiation emissions were detected using a 1mm thin circle of copper wire. Pre-history of Radio Waves Now that there is evidence of electromag- It is almost impossible to depict the most im- netic waves, the physicist Max Planck (1858-1947) portant facts in the history of radio astronomy with- was responsible for a breakthrough in physics that out presenting a sneak peak where everything later developed into the quantum theory, which sug- started, the development and understanding of the gests that energy had to be emitted or absorbed in electromagnetic spectrum.
[Show full text]
Radio Astronomy
Edition of 2013 HANDBOOK ON RADIO ASTRONOMY International Telecommunication Union Sales and Marketing Division Place des Nations *38650* CH-1211 Geneva 20 Switzerland Fax: +41 22 730 5194 Printed in Switzerland Tel.: +41 22 730 6141 Geneva, 2013 E-mail: [email protected] ISBN: 978-92-61-14481-4 Edition of 2013 Web: www.itu.int/publications Photo credit: ATCA David Smyth HANDBOOK ON RADIO ASTRONOMY Radiocommunication Bureau Handbook on Radio Astronomy Third Edition EDITION OF 2013 RADIOCOMMUNICATION BUREAU Cover photo: Six identical 22-m antennas make up CSIRO's Australia Telescope Compact Array, an earth-rotation synthesis telescope located at the Paul Wild Observatory. Credit: David Smyth. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. - iii - Introduction to the third edition by the Chairman of ITU-R Working Party 7D (Radio Astronomy) It is an honour and privilege to present the third edition of the Handbook – Radio Astronomy, and I do so with great pleasure. The Handbook is not intended as a source book on radio astronomy, but is concerned principally with those aspects of radio astronomy that are relevant to frequency coordination, that is, the management of radio spectrum usage in order to minimize interference between radiocommunication services. Radio astronomy does not involve the transmission of radiowaves in the frequency bands allocated for its operation, and cannot cause harmful interference to other services. On the other hand, the received cosmic signals are usually extremely weak, and transmissions of other services can interfere with such signals.
[Show full text]
Adventures in Radio Astronomy Instrumentation and Signal Processing
Adventures in Radio Astronomy Instrumentation and Signal Processing by Peter Leonard McMahon Submitted to the Department of Electrical Engineering in partial fulﬁllment of the requirements for the degree of Master of Science in Electrical Engineering at the University of Cape Town July 2008 Supervisor: Professor Michael Inggs Co-supervisors: Dr Dan Werthimer, CASPER1, University of California, Berkeley Dr Alan Langman, Karoo Array Telescope arXiv:1109.0416v1 [astro-ph.IM] 2 Sep 2011 1Center for Astronomy Signal Processing and Electronics Research Abstract This thesis describes the design and implementation of several instruments for digi- tizing and processing analogue astronomical signals collected using radio telescopes. Modern radio telescopes have signiﬁcant digital signal processing demands that are typically best met using custom processing engines implemented in Field Pro- grammable Gate Arrays. These demands essentially stem from the ever-larger ana- logue bandwidths that astronomers wish to observe, resulting in large data volumes that need to be processed in real time. We focused on the development of spectrometers for enabling improved pulsar2 sci- ence on the Allen Telescope Array, the Hartebeesthoek Radio Observatory telescope, the Nan¸cay Radio Telescope, and the Parkes Radio Telescope. We also present work that we conducted on the development of real-time pulsar timing instrumentation. All the work described in this thesis was carried out using generic astronomy pro- cessing tools and hardware developed by the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California, Berkeley. We successfully deployed to several telescopes instruments that were built solely with CASPER technology, which has helped to validate the approach to developing radio astronomy instruments that CASPER advocates.
[Show full text]
NRAO Enews Volume 12, Issue 5 • 13 June 2019
NRAO eNews Volume 12, Issue 5 • 13 June 2019 Upcoming Events NRAO Community Day at UMBC (https://science.nrao.edu/science/meetings/2019/umbc19/index) Jun 13 14, 2019 | Baltimore, MD CASCA 2019 (http://www.physics.mcgill.ca/casca2019/) Jun 17 20, 2019 | Montréal, Québec Radio/mm Astrophysical Frontiers in the Next Decade (http://go.nrao.edu/ngVLA19) Jun 25 27, 2019 | Charlottesville, VA 7th VLA Data Reduction Workshop (http://go.nrao.edu/vladrw) Oct 7 18, 2019 | Socorro, NM ALMA2019: Science Results and CrossFacility Synergies (http://www.eso.org/sci/meetings/2019/ALMA2019Cagliari.html) Oct 14 18, 2019 | Cagliari, Sardinia, Italy Semester 2019B Proposal Outcomes Lewis Ball The NRAO has completed the Semester 2019B proposal review and time allocation process (https://science.nrao.edu/observing/proposal-types/peta) for the Very Large Array (VLA) (https://science.nrao.edu/facilities/evla) and the Very Long Baseline Array (VLBA) (https://science.nrao.edu/facilities/vlba) . For the VLA a single configuration (the D array) will be available in the 19B semester and 124 new proposals were received by the 1 February 2019 submission deadline including one large and sixteen time critical (triggered) proposals. The oversubscription rate (by proposal number) was 2.5 and the proposal pressure (hours requested over hours available) was 2.1, both of which are similar to recent semesters. For the VLBA 27 new proposals were submitted, including two large proposals and one triggered proposal. The oversubscription rate was 2.1 and the proposal pressure was 2.3, both of which are similar to recent semesters.
[Show full text]
2020 the Pathfinder View of the Sky LEGEND Canadian Hydrogen Intensity Mapping European VLBI Experiment (CHIME) - Network (EVN) - Canada Europe
Calendar 2020 The Pathfinder View of the Sky LEGEND Canadian Hydrogen Intensity Mapping European VLBI Experiment (CHIME) - Network (EVN) - Canada Europe enhanced Multi Element Remotely NenuFAR - France Linked Interferometer Network (e-MERLIN) - United Kingdom Low Frequency Array (LOFAR) - the MeerKAT Radio Netherlands Telescope - South Africa Five-hundred-meter Aperture Spherical Australian SKA Telescope (FAST) - Pathﬁnder (ASKAP) - China Australia (CHIME) Giant Metrewave Murchison Wideﬁeld Radio Telescope Array (MWA) - (GMRT) - India Australia VLBI Exploration of Effelsberg 100m Members of the SKA Organisation African Partner Countries Radio Astrometry Radio Telescope - Host Countries: Australia, South Africa, United Kingdom (VERA) - Japan Germany In the lead up to the SKA, many new groundbreaking radio elusive Fast Radio Bursts. They’re also allowing engineers The 2020 SKA calendar, called The Pathfinder View of the astronomy facilities have sprung up around the world in to develop new technical solutions like aperture arrays or Sky and featuring a small selection of the results already the past 10 years. These facilities are part of a global Phased Array Feeds. In so doing, they are paving the way coming out of 12 of these telescopes, is our tribute to effort to design and build ever-more sensitive instruments for the world’s largest radio telescope, the SKA. the pathfinder family as a whole, the people who have built to detect some of the faintest signals in the universe them and the people who are using them. The knowledge These facilities are now open to the community or going and grow new scientific and technical communities while and experience they’ve accumulated will guide us through through commissioning, and already they are providing benefiting society through cutting-edge R&D.
[Show full text]
Kraus Transcript.Pdf (118.8Kb)
INTERVIEW WITH DR. JOHN KRAUS AUGUST 20, 2002 Q. This is Robert Wagner. I’m at the home of Dr. John Kraus, who is Professor of Electrical Engineering and Astronomy Emeritus at Ohio State. And we’re recording this interview on August 20, 2002. Dr. Kraus, do you want to proceed and give us a little introduction to your work? A. Yes, I thought about your questions and I would like to say some things that relate to my impressions when I came to Ohio State in 1946. This was just after World War II. The students in those classes were some of the most serious and best students I ever had. It was a stimulating atmosphere. Within a few months of being at Ohio State, I made an invention in the basement of my home, the helical antenna, which soon became in use worldwide, and especially on satellites in space. It’s one of the main antennas that are used in space communication. The satellites that are up there and the space station and others use them. I had always been interested in astronomy and had made some experiments years ago to detect radio waves on the sun unsuccessfully. That was in 1932. Anyhow, the idea of building an array of these helical antennas a couple feet in diameter and ten feet long, putting up this array, 96 of them on the corner of the University farms that Dean Rummell, the Dean of Agriculture, said I could use, I thought was an exciting prospect because it would give Ohio State a radio telescope, one of the first built.
[Show full text]
Science Pipelines for the Square Kilometre Array
galaxies Article Science Pipelines for the Square Kilometre Array Jamie Farnes * , Ben Mort, Fred Dulwich, Stef Salvini and Wes Armour Oxford e-Research Centre (OeRC), Department of Engineering Science, University of Oxford, Oxford OX1 3QG, UK; [email protected] (B.M.); [email protected] (F.D.); [email protected] (S.S.); [email protected] (W.A.) * Correspondence: [email protected] Received: 5 October 2018; Accepted: 15 November 2018; Published: 20 November 2018 Abstract: The Square Kilometre Array (SKA) will be both the largest radio telescope ever constructed and the largest Big Data project in the known Universe. The first phase of the project will generate on the order of five zettabytes of data per year. A critical task for the SKA will be its ability to process data for science, which will need to be conducted by science pipelines. Together with polarization data from the LOFAR Multifrequency Snapshot Sky Survey (MSSS), we have been developing a realistic SKA-like science pipeline that can handle the large data volumes generated by LOFAR at 150 MHz. The pipeline uses task-based parallelism to image, detect sources and perform Faraday tomography across the entire LOFAR sky. The project thereby provides a unique opportunity to contribute to the technological development of the SKA telescope, while simultaneously enabling cutting-edge scientific results. In this paper, we provide an update on current efforts to develop a science pipeline that can enable tight constraints on the magnetised large-scale structure of the Universe.
[Show full text]
Basics of Radio Astronomy I
Introduction to Radio Astronomy • Sources of radio emission • Temperature: Blackbody radiation in radio astronomy • Radio telescope characteristics • Why radio astronomy is different from optical astronomy Sources of Radio Emission • Blackbody (thermal) • Continuum sources (non-thermal) • Spectral line sources Blackbody Sources: The cosmic microwave background, the planets, etc • Obs in cm requires low temperature: lmT = 0.2898 cm K • Flux = const ´ na ´ TlmT = 0.2898 cm K • For thermal sources a is ~2 (flatter for less opaque sources) Continuum (non-thermal) Emission: Emission at all radio wavelengths Bremsstralung (free-free): Electron is accelerated as it passes a charged particle thereby emitting a photon Synchrotron: A charged particle moving in a magnetic field experiences acceleration and emits a photon Sources of Continuum Emission 21cm Line of Neutral Hydrogen, cont. • HI spectral line from galaxy • Shifted by expansion of universe (recession velocity) • Broadened by rotation Radio Telescope Characteristics sensitivity • Sensitivity is a measure of the relationship between the signal and the noise • Signal: the power detected by the telescope • Noise: mostly thermal from electronics but also ground radiation entering feedhorn and the cosmic microwave background. Poisson noise is ALWAYS important. Interference is also a HUGE problem (radar, GPS, etc.) Radio Telescope Characteristics semantics • Preferred unit of flux density: (requires calibration) is Jansky: 1Jy = 10-26 W m-2 Hz-1 • Brightness: Flux density per unit solid angle.
[Show full text]
Radio Astronomy Facilities
RadioRadio AstronomyAstronomy FacilitiesFacilities Exploring the Cosmic Frontier Berlin May 18 Ron Ekers CSIRO, Australia 1 OutlineOutline A Brief History of Radio Astronomy Astronomy at radio wave lengths Impact of new technology Science Opportunities – Key experiments with some of the proposed facilities Future Facilities – e-MERLIN – EVLA I & II – ATA – GMRT, LOFAR – FPA’s (Parkes, Arecibo) – SKA, DSN array – ALMA 2 RadioRadio TelescopeTelescope SensitivitySensitivity 5 Reber 4 Exponential increase Jansky 1931 - the beginning 5 ity 3 Dwingeloo in sensitivity x 10 itiv s since 1940 ! n 2 Jodrell Bank e Parkes » 3 year doubling time for S Bonn e 1 sensitivity WSRT tiv Arecibo la 0 AT e VLA R GMRT -1g 1hT o GBT L -2 SKA -3 1940 1950 1960 1970 1980 1990 2000 2010 Date 3 TheThe 33 NobelNobel prizesprizes inin RadioRadio AstronomyAstronomy Cosmic Microwave Background (1965) – Nobel prize to Penzias and Wilson » Bell Telephone Labs – Technology driven serendipity Discovery of neutron stars – radio pulsations (pulsars) – Jocelyn Bell & Tony Hewish Verification of Einstein's prediction of gravitational radiation – 1993 Noble prize to Taylor and Hulse ProvidesProvides uniqueunique informationinformation aboutabout thethe UniverseUniverse Non-thermal processes: quasars, pulsars, masers... Highest angular resolution: – VLBI Penetrates dust and gas: Protostars Galactic nuclei Tracer for Cosmic Magnetic fields Beck 5 RadioRadio TelescopeTelescope SensitivitySensitivity 5 Reber 4 Exponential increase in 5 ity sensitivity x 10 since 3
[Show full text]
Square Kilometre Array
Square Kilometre Array John Conway Onsala Space Observatory, 18 June 2012 Radio Observations for Astronomy • Astrophysics today requires ‘pan-spectral’ data – but radio provides unique information. • ‘Radio’ astronomy one of two EM windows visible from Earth’s surface. • Encompasses 10 MHz – 1 THz 5 (factor of 10 in frequency, needs multiple technologies!). The optical/IR window covers just over factor of 30. • Radio unique properties- Obscuration independent - high angular resolution (1mas) – unique lines – magnetic fields. Radio Telescope Sensitivity Evolution Sensitivity improves 107 in 80 yrs(collecting area, receivers and Bandwidth) Groet Reber’s Backyard SKA (2020+)- 40 telescope (1940) times EVLA Today’s State of Art • To get high resolution need interferometers, resolution inversely proportional to longest baseline - large single dishes (i.e Arecibo) less important cm-wave mm-wave EVLA (Jansky Very Large Array) – Atacama Large Millimetre Array refurbished VLA, New Mexico USA (ALMA) – 5000m altitude Chile. 20 – 27 x 25m diameter dishes dishes now soon 66 dishes of 12m 300MHz – 50GHz diameter – 90GHz – 800 GHz FUTURE RADIO TELESCOPES 2012 2013 2014 2015 2016 2017 2018 2019 2020 m -wave LOFAR (NL/ Europe) MeerKAT (S.Africa) Jansky VLA Square Kilometre Array – cm -wave SKA (S. Africa and Australia/NZ) – (cm) 50 times EVLA (m) 10 times LOFAR ASKAP(Australia) ALMA mm -wave (Chile) Great Observatories for the coming decades ALMA mm/ sub-mm E-ELT optical SKA JWST infra-red radio IXO Xray Top-level description • Construction will proceed
[Show full text]
Radio Astronomy Module
Radio Astronomy module Contact [email protected] Notes: NRAO Essential radio astronomy course: http://www.cv.nrao.edu/course/astr534/ERA.shtml See also http://www.haystack.mit.edu/ edu/undergrad/materials/RA_tutorial.html Radio Astronomy: Past and Future Outline The discovery of radio emission from the sky Early instruments SKA South Africa's role in the SKA meerKAT − XDM − KAT-7 Prehistory of RA Oliver Lodge and Nikolai Tesla atttempted to detect signals from the Sun − Too much interference − Too little sensitivity The 1920's -1930's Bell Telephone initiates a “shortwave” transatlantic service Communications are disrupted by static Karl Jansky tasked to determine its orgin: − Mostly tropical thunderstorms − Steady “hiss” that rose and fell daily with a period of 23:56 − Direction of Galactic centre strongest source Proposal for another antenna and further study rejected and he was reassigned Karl Jansky Jansky's 'merry-go-round' 20.5 MHz 100 ft diameter Rotated manually on a set of 4 Ford Model-T tires Grote Reber (1930's) Learned about Jansky's discovery and wanted to follow up Couldn't get a job at Bell labs or observatories because of the Great Depression So he decided to study on his own Grote Reber Built telescope at his own expense in his backyard 31.4 ft diameter (~9m) Grote Reber Worked at night because of interference from car engines 3300 MHz, failed to detect anything 900 MHz, failed 160 MHz, successful in 1938 Grote Reber's recordings 1943 First radio map of the galaxy Grote Reber (9m) WWII Radar Delevopment
[Show full text]
Historical Introduction to Radio Astronomy
Historical Introduction to Radio Astronomy Robert L. Brown National Astronomy and Ionosphere Center Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 1 Definitions: “Radio Astronomy ” Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 2 1 Chronology of Radio Communication Technology 1901 Marconi —First transatlantic Radio Communicaton ► ► Frequency < 100 kHz ► ► Limitations: Bandwidth, “atmospherics” 1920 “Shortwave” —intercontinental communication ► ► Frequency 1.5 MHz ► ► Technology: Vacuum triode tubes ► ► Limitations: Bandwidth, “atmospherics” 1927 AT&T Longwave transatlantic telephony (voice ) ► ► Frequency 60 kHz ► ► Enabling Technology: Directional Antenna Design ► ► Limitations: Bandwidth, “atmospherics” 1929 AT&T shortwave transatlantic telephony (voice) ► ► Frequency: 9 – 21 MHz ► ► Enabling Technology: Quartz Crystal Oscillator ► ► Limitations: “Atmospherics”, RFI, Antenna Directionality 1928 Karl Jansky joins AT&T Bell Labs Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 3 Karl Jansky The Discovery of Cosmic Radio Emission Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 4 2 Karl Jansky The Discovery of Cosmic Radio Emission Jansky’s Task and Resources at Bell Labs Task : Identify the optimum frequency and technology requirements fo r shortwave transatlantic communication Resources : ► ► Modified “Bruce Array” of tuned, quarter -wave elements giving good directionality (wavelength 14.6m, frequency 20.5 MHz) ► ► Superheterodyne receiver stable enough to integrate for long times (30 sec) with a bandwidth of 26 kHz (BW/RF ~ 0.1%) Technique : Rotate antenna in azimuth every 20 minutes scanning the sky [From “The Early Years of Radio Astronomy”, ed W. T. Sullivan II I] Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 5 Robert L. Brown 2005 NAIC/NRAO Single Dish Summer School 6 3 Robert L.
[Show full text]