GMRT Full Form
What is the full form of GMRT?
The full form of GMRT is the Giant Metrewave Radio Telescope, a radio telescope used worldwide to observe astronomical objects such as pulsars, supernovae, galaxies and Sun and solar winds. In India, it is located near Pune. It is operated by the National Centre for Radio Astrophysics and was built under the supervision of Govind Swarup.
The frequency of GMRT ranges from 50 MHz to 1450 MHz. The main purpose of GMRT is to detect cosmic radio waves and to support interferometry. 40% of its users belong to India, and 60% are from outside.
Many antennas are used in GMRT to build a structure like a long-range antenna. Therefore, it is capable of detecting long wavelengths as well.
Site of GMRT
GMRT is located about 10 km east of Narayangaon town, on the Pune highway, The site was selected after an extensive search in different parts of India, keeping in mind several criteria like low man-made radio noise, vicinity of industrial, availability of good communication, educational and other infrastructure and, a geographical latitude which is north of the geomagnetic equator to have a reasonably quiet ionosphere and be able to observe the southern sky as well.
Antennae Configuration
The configuration and number of the dishes were optimised to meet the principal astrophysical objectives, which need sensitivity at high angular resolution and the ability to image radio emission from diffuse extended regions. Of the thirty dishes, fourteen are located randomly in a compact Central Array region of 1 sq km. And the remaining 16 dishes are spread out widely along the three arms of an approximately `Y'-Shaped configuration with the longest interferometric baseline of 25 km.
Design and Structure
GMRT is a project where the construction of thirty large dishes at a relatively small cost has been possible because of a technological design achieved by Indian Scientists and Engineers, including lightweight and low-cost dishes. The design was based on the ‘SMART’ concept for Stretch Mesh Attached to Rope Trusses.
The lightweight dishes have been made of low solidity by replacing the conventional structure with rope trusses stretched between sixteen parabolic frames made of tubular steel. The wire ropes are placed to make a mosaic of plane facets approximating a parabolic surface. Also, lightweight, thin wire meshes are stretched over the rope truss facets to form the reflecting surface of the dish.
This low-solidity design helps to cut down the wind forces and is well-suited to Indian climates where there is no snowfall in the plains. The wind forces and the torques for a 45-m GMRT dish are like those for only a 22-m dish of conventional design, which helped to reduce the cost.
The dish is connected to a `cradle' supported by 2 elevation bearings on a yoke placed on a 3.6 m diameter slewing-ring bearing, secured on the top of a 15-meter high concrete tower. The disk weighs about 80 tons, and the counterweight is approximately 40 tons. The dishes also have the alt-azimuth mount.
Latest developments in GMRT
The latest upgrade in 2019 has helped improve the sensitivity of GMRTby three times, making it capable of detecting fainter and faraway sources of the universe. This upgraded version is known as uGMRT, and has more sensitivity than GMRT. The upgradation of GMRT was achieved by increasing the number of antennas and separating the antennas. The GMRT is an important instrument in astronomical studies which gives information about the activities in the universe.
One of the most distant galaxies, located at a distance of 12 billion light-years, was discovered on August 2018 by GMRT.
GMRT helped observe the biggest explosion in the universe's history in February 2020. The explosion was also known as the Ophiuchus Supercluster explosion.
GMRT received the IEEE Milestone award in 2020, honouring technical achievements and excellence in unique objects and services.
The Institute of Electrical and Electronics Engineers (IEEE) is the world’s largest technical organisation committed to advancing electrical and electronics engineering technologies.
Uses of GMRT
GMRT is used mainly for the screening of astrophysical objects and phenomena.
It is an instrument for investigating different radio astrophysical problems extending from the nearby Solar system to the edge of the observable Universe.
The telescope can also be used to observe the sky at various frequencies.
GMRT has been used to study various objects in the Milky Way and gasses' structure, content and nature in external galaxies.
It has helped study the effect of star radiation on various galaxies.
Frequently Asked Questions (FAQs)
GMRT, a Giant Metrewave Radio wave Telescope, is used to investigate various radio astrophysical problems ranging from the nearby Solar system to the edge of the observable Universe.
Giant Metrewave Radio wave Telescope is used for radio waves.
The first purpose-built radio telescope was a 9-meter high parabolic dish constructed by radio amateur Grote Reber in his backyard in Wheaton, Illinois, in 1937.
Keeping in mind the growth of low-frequency radio astronomy in the world and learning from our own experiences of building and using the GMRT, a plan to upgrade the GMRT was proposed during the 11th Plan funding period (2007−2012), and the first serious work in this direction was initiated around 2010.
One of the advantages of radio telescopes is that they can be used in cloudy weather since radio waves can pass through clouds. But the disadvantage of these instruments is that they need a large collecting area, so they are expensive to construct.