What is a liquid mirror telescope, the first Indian telescope in Uttarakhand

The country’s first liquid mirror telescope and Asia’s largest — operating over Devastal, a hill in Uttarakhand — will now monitor the upper skies to identify transiting or shifting objects such as supernovae, gravitational lenses, space debris and asteroids.

The Indian Liquid Mirror Telescope (ILMT) will help survey the sky, making it possible to observe many galaxies and other astronomical sources simply by gazing at the celestial blade passing through the sky.

Created by astronomers from India, Belgium and Canada, the new device uses a 4 meter diameter rotating mirror made of a thin layer of liquid mercury to collect and focus light. It is located at an altitude of 2,450 meters on the campus of the Devasthal Observatory of Aryabhatta Research Institute of Monitoring Sciences (ARIES), an independent institution under the Ministry of Science and Technology (DST), Government of India in Nainital District, Uttarakhand.

Scientists from three countries twisted a collection of mercury, a reflective liquid, so that its surface curved into a parabolic shape. It is ideal for focusing light. A thin transparent layer of mylar protects the mercury from the wind. The reflected light passes through an advanced multi-lens optical corrector that produces sharp images across a wide field of view. A large electronic camera on the focus of recording images.

Paul Hickson of the University of British Columbia, Canada, an expert on liquid mirror technology, said, “Earth’s rotation causes the image to drift through the camera, but this motion is compensated electronically by the camera. This mode of operation improves monitoring efficiency and makes the telescope highly sensitive to dim and scattered objects.

“ILMT is the first liquid mirror telescope specifically designed for astronomical observations to be installed at the ARIES Devasthal Observatory,” said Dipankar Banerjee, ARIES Director.

The Devasthal Observatory now has two four-meter class telescopes – the ILMT and the Devasthal Optical Telescope (DOT).

The telescope was designed and built by Advanced Mechanical and Optical Systems (AMOS) and the Center Spatial de Liege in Belgium.

The ILMT collaboration includes researchers from ARIES in India; the University of Liège and the Royal Belgian Observatory in Belgium; Poznan Observatory in Poland; Oleg Beg Institute of Astronomy of Uzbekistan, National Academy of Sciences and University of Uzbekistan; The University of British Columbia, University of Laval, University of Montreal, University of Toronto, York University, and Victoria University are all in Canada.

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