A new telescope facility atop a mountain in the Himalayan range will now keep a watch on the overhead sky to identify transient or variable objects such as supernovae, gravitational lenses, space debris, and asteroids.
What is it?
- A liquid mirror telescope, as its name suggests, uses a liquid, not aluminised glass, as its primary mirror.
- The liquid, usually mercury, is poured into a rotating dish.
- The rotation creates two fundamental forces that act on the mercury — gravity and inertia.
- Gravity pulls down on the liquid surface, while inertia pulls the liquid sideways at the edge of the dish.
- As a result, the liquid forms a uniform and perfect parabola, the ideal reflecting surface for a telescope.
- Best of all, the liquid mirror surface remains smooth and flawless with little or no maintenance.
- If the liquid is disturbed, gravity and inertia will act on the liquid to return it to its original state.
History of LMT –
- Ernesto Capocci, an Italian astronomer, was the first person to describe how an LMT might work in 1850.
- Modern astronomers learned that the image quality of an LMT was greatly improved if a thinner layer of mercury was used, so today’s LMTs use a one-millimetre layer of mercury.
How is LMT different from Optical Telescope?
- An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors.
- Unlike optical telescope, an LMT remains stationary as it cannot be turned and pointed in any direction.
- It “stares” at the zenith and watches the sky as the Earth rotates, thereby giving a view of different objects.
About Devasthal LMT –
- India’s first liquid-mirror telescope, which will observe asteroids, supernovae, space debris and all other celestial objects from an altitude of 2,450 metres in the Himalayas, has seen its first light.
- It has now entered the commissioning phase and will start scientific observations by October, 2022.
- It is established on the campus of the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES) in Nainital, Uttarakhand.
- Known as the International Liquid Mirror Telescope (ILMT), it is the only liquid-mirror telescope operational anywhere in the world.
- It will also hold the unique tag of being the maiden liquid-telescope globally to be designed exclusively for astronomical purposes.
Why India’s majority telescopes are stationed at Devasthal Observatory?
- This site was chosen after an extensive site characterisation conducted during 1980 – 2001 in the central Himalayan range.
- The main advantages of Devasthal site are in its dark skies, sub-arcsec seeing, low extinction and at the same time being easily assessable and manageable.
- In total, 41,692 square meter of land has been transferred to ARIES from Uttarakhand Government which includes roads, base camp area and telescope site.
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