Radio telescopes are used to identify and study naturally-occurring radio light from stars, galaxies, black holes, pulsars and many more astronomical objects. While they are used to receive radio light, we can also use radio telescopes to transmit and reflect radio light off of planetary bodies in our solar system.
Radio Telescopes observe the longest wavelengths of light which can range from 1 millimetre to over 10 meters long. To give you a comparison between the sizes, visible light waves are only a few hundred nanometres long.
These devices are typically made up of several elements; in one of their most familiar forms, each radio telescope has an antenna, receiver, amplifier, feed horn and dish. Due to cosmic radio sources being extremely weak, radio telescopes are some of the largest telescopes in the world. Due to the incredibly sensitive equipment they use to detect radio light, any modern electronics can cause background interference, which is why many are situated miles from the nearest human populace as possible or have a Quite Zone setup around them, where officials track down any offending pieces of equipment.
VLA Radio Telescope / Karl G. Jansky Very Large Array – Socorro, New Mexico
The Very Large Array is a radio telescope array that consists of 27 25-meter radio telescopes in Y-shaped arrays. Each dish has a diameter of 25 meters; the antennae are distributed along 3 arms of a track, measuring 13 miles in length. With the help of a ‘Heins Trein’ and rails, these antennas can be physically relocated to a number of prepared positons
Starting operation in 1980 the observation was upgraded in in 2011, resulting in expanding its technical capacities by factors of 8,000 (apparently).
The observation is one of the most versatile and widely used radio telescopes in the world, it can map large-scale structures of gas and molecular clouds and pin point ejections of plasma from super massive black holes. It was the first colour camera for radio astronomy and has been used to discover a range of astronomical objects, including Ice on Mercury, Supermassive black holes such as the one in the ‘Henize 2-10’ galaxy, other discovery’s include micro quasars, Einstein’s Rings and the nature of gamma-ray bursts.
Mount Pleasant Radio Telescope – Tasmania, Australia
Mount Pleasant Radio Observatory is a radio astronomy based observatory, the observatory has 3 radio telescopes: the Mount Pleasant 26 metre antenna, the 14 metre Vela Antenna and a 12 metre AuScope VLBI Antenna, which is all linked to the University of Tasmania over 35km of optical cable.
By Noodle snacks (Own work) [CC BY-SA 3.0 or GFDL], via Wikimedia Commons
The 26 metre radio telescope originally came from the Orroral Valley Tracking station, while the 14 metre Vela was purposely built as a dedicated instrument for observation of the Vela Pulsar which it has been tracking 18 hours a day for nearly 20 years.
IRAM 30 m Radio Telescope – Sierra Nevada, Spain
IRAM is an international research institute for radio astronomy that operates a 30 metre diameter telescope that began operation in 1984 and is equipped with a series of heterodyne receivers and continuum cameras operating at 3, 2, 1, and 0.9mm millimetres.
High resolution spectroscopy allows the study of the interplay of chemistry and the ongoing formation of starts within giant molecular clouds of the Milky Way and nearby galaxies, and out to the farthest known galaxies of the young universe.
Discoveries include: The discovery of a new interstellar molecule confirms the existence of a petroleum refinery in our galaxy, NOEMA discovers previously unknown extreme star formation region – the ‘Eye of Medusa’, Discovery of an extremely bright dust-enshrouded galaxy in the Early Universe and much more.
Parkes Radio Telescope – New South Wales, Australia
The Parkes radio telescope dish measures 64 metres in diameter; it can rotate 360 degrees and can tilt 60 degrees from vertical and It started operation in 1961 and still continues to with the help of regular upgrades.
It was also one of several radio antennas used to receive live, televised images of the Apollo 11 moon landing in 1969. During the Apollo mission to the moon The Parkes Observatory was used to relay communication and telemetry signals to NASA, providing coverage for when the moon was on the Australian side of the Earth.
Other roles it played a part in, include: Relaying data from NASA’s Galileo mission to Jupiter that required radio-telescope support, and was used to track numerous space missions such as, Mariner 2, Mariner 4, Voyager, Giotte, Galileo, and Cassini-Huygens.
Atacama Large Millimetre Array (ALMA) – Sierra Negra, Mexico
Atacama Large Millimetre Array is an astronomical interferometer of radio telescopes in the Atacama Desert that consists of 66 12-meter (39 ft.) diameter radio telescopes. Alma observes at
millimetre and submillimetre wavelengths, and is expected to provide an understanding on star birth during the early universe, while providing detailed imaging of local start and planet formations.
The ALMA is an international partnership among Europe, US, Canada, East Asia and the republic of Chile and total costs came to $1.4 billion and became operational in 2013.
Discoveries include: The best submillimetre-wavelength image ever made of the Antennae Galaxies, an image of the protoplanetary disk surrounding ‘HI Tauri’ (made public in 2014), also giving scientists the ability to search for Exoplanets, allows the determination of the age of the universe, ALMA showed a disk of gas and cosmic dust around the young star HD 142527 which is helping to explain how young stars are formed. These are only some of the discoveries and ALMA has only been up and running since
Lovell Radio Telescope – Cheshire, England
The Jodrell Bank Observatory is 76 m in diameter, it was the largest steerable dish radio in the world when it was finished in 1957; it’s now 3rd after being taken over by the ‘Green Bank’ telescope and the ‘Effelsberg’.
This telescope was the only one in the world able to track Sputniks booster rocket by radar. In the years following the telescope was used for a huge variety of space probes, such as the Pioneer 5 probe, and was also used to send commands back to it.
Effelsberg Radio Telescope – Effelsberg, Germany
The Effelsberg began operation in 1971 and was the largest fully steerable radio telescope at 100 m in diameter until 2000 when the Green Bank Telescope was constructed.
A major technical difficulty in building a radio telescope of 100 m diameter was how to deal with the deformation of the parabolic mirror moves and tilts, the Finite element method was used to construct the mirror supports in such a way that the deformed mirror will always take a parabolic shape.
By Dr. Schorsch (photo taken by Dr. Schorsch) [GFDL, CC-BY-SA-3.0 or CC BY-SA 3.0], via Wikimedia Commons
Discoveries include: detecting water at the greatest distance from earth yet (11 billion light years), first discovery of an extragalactic water maser, a detailed radio map of the Andromeda Galaxy, discovery of the Geodetic precession in B1913+16, 42 new supernova remnants were discovered in the 11cm galactic plane survey, and much more.
Green Bank Radio Telescope – West Virginia, USA
The Green Bank radio telescope has a 100 m by 110 m dish making it the world’s largest fully steerable radio telescope, as well as being the world’s largest moveable land object and began operation in 2002. At 17 million pounds of telescopes sits on a concrete support which is sunk down 25 foot bedrock, all of which glides around on its 360 degree concrete track.
By Geremia at English Wikipedia [Public domain], via Wikimedia Commons
Due to the way the 200 foot feed arm works, the waves are bounced up to a secondary mirror perched 60 feet above the dish, the secondary focuses radio waves onto a rotating turret holding the 8 receivers allowing the receiver to be changed at need to measure a different frequency.
Discoveries include: faint gas clouds between galaxies, the hidden chemistry between the stars, and has given scientists the ability to measure values such as pulsar timings and interpret values for dark matter and energy.
The Arecibo Observatory – Puerto Rico
One of the most famous Radio Telescopes, most people won’t of known what this massive structure was and where probably too busy during James Bonds fight scene in ‘’Golden Eye’’.
The structure measures 305 m (1,000 feet) in diameter and was built in 1963, the collecting area itself is a massive 74,000 square metres (790,000 sq ft).
The radio telescope being the world’s largest single-aperture telescope (until FLASH finishes construction) and is used for 3 major areas of research: radio astronomy, atmospheric science and radar astronomy.
The discoveries include: the rotation speed of mercury, discovered the periodicity of the Crab Pulsar (33 milliseconds), provided the first solid evidence that neutron stars exist, discovery of the first binary pulsar, the observatory directly imaged an asteroid for the first time in history, map the distribution of ice in the polar regions of mercury and detection of prebiotic molecules- methenamine and hydrogen cyanide using radio spectroscopy.
FAST Project – Five hundred meter Aperture Spherical Telescope – Guizhou, China
The Five hundred metre Aperture Spherical Telescope (FAST) is a radio telescope under construction in a natural basin in Pingtang, Guizhou, China. Construction began in 2011 and is thought to be completed by September 2016, once built it will be the world’s largest and most sensitive radio telescope, 3x more sensitive than the Arecibo Observatory.
Unlike the Arecibo Observatory however it has an active surface that adjusts to create parabolas in different directions, with an effective dish size of 300m. This allows it the capability to cover 40 degrees from the zenith.
It’s thought that FLASH’s unprecedented precision will allow astronomers to survey the Milky Way, other galaxies, detect even fainter pulsars, help search for extra-terrestrial life and possibility play key roles in future space programs.
