Indian scientists develop low-cost telescopic gadget to view distant celestial objects

Vijay Mohan

Tribune News Service

Chandigarh, March 3

Indian scientists have indigenously designed and developed a low-cost optical spectrograph that can locate sources of faint light from distant quasars and galaxies in a very young universe, regions around super massive black-holes and cosmic explosions.

Such spectroscopes were so far imported at high costs. The Indian spectrograph, named Aries–Devasthal Faint Object Spectrograph and Camera (ADFOSC), cost nearly Rs 4 crore, which is about 40 per cent of the price of the imported equipment.

Designed and developed by Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, it is the largest of its kind among the existing astronomical spectrographs in the country. The spectrograph has been commissioned on the 3.6-m Devasthal Optical Telescope (DOT) located near Nainital, which is the largest in Asia.

ADFOSC can locate sources of light with a photon-rate as low as about one photon per second and forms the backbone of DOT for observations of extremely faint celestial sources. It uses a complex arrangement of several lenses made of special, highly polished glasses to produce sharp images of the sky.

Photons coming from distant celestial sources, collected by the telescope, are sorted into different colours by the spectrograph and are finally converted into electronic recordable signals using an in-house developed Charge-Coupled Device (CCD) camera cooled to an extremely low temperature of minus 120 degrees Celsius.

The technical and scientific team that researched and developed various optical, mechanical and electronic sub-systems of the spectrograph and camera was led by Dr Amitesh Omar. The spectrograph is being used by astronomers from India and abroad to study distant quasars, which are massive and extremely remote celestial objects emitting exceptionally large amounts of energy, and galaxies, highly energetic gamma-ray bursts, young and massive stars as well as faint dwarf galaxies.

Experts from various national institutes including the Indian Space Research Organisation and some micro-small-medium-enterprises were also involved to review and build parts of the ADFOSC.

With this development, ARIES now plans to commission more complex instruments such as spectro-polarimeter and high spectral resolution spectrograph on the DOT in the near future, according to a statement issued by the Ministry of Science and Technology.