Indian scientists develop low-cost spectrograph that can locate faint light from distant celestial objects


In a significant development, Indian Scientists have indigenously designed and developed a low-cost optical spectrograph, which is capable of locating sources of faint light from distant celestial objects. 

The spectrograph can detect faint light from distant quasars and galaxies, regions around supermassive black-holes and cosmic explosions.

The ‘Made in India’ optical spectrograph has been named as Aries-Devasthal Faint Object Spectrograph & Camera (ADFOSC). 

Key Details 

•  The ‘Made in India’ spectrograph has been indigenously designed and developed by Aryabhatta Research Institute of observational sciences (ARIES), Nainital.

•  The spectrograph has been successfully commissioned on the 3.6-m Devasthal Optical Telescope (DOT), which is the largest in India and Asia.
•  It is the largest among the existing astronomical spectrographs across India. 


•  The indigenously-developed spectrograph can locate sources of light with a photon-rate as low as about 1 photon per second.

•  Such spectroscopes were so far imported from abroad at high costs but the ‘Made in India’s spectrograph is almost 2.5 times less costly than the imported ones. 

How does a spectrograph work?

•  The spectrograph uses a complex arrangement of several lenses made of special glasses, which are polished to better than 5-nanometer smoothness to produce sharp images of the celestial sky. 

•  The telescope collects photons coming from distant celestial sources, which are then sorted into different colors by the spectrograph and converted into electronic recordable signals using an in-house developed Charge-Coupled Device (CCD) camera that is cooled to an extremely low temperature of -120 degree celsius. 

•  The total cost of this instrument is almost Rs 4 Crore.

The spectrograph is used by astronomers to study distant quasars and galaxies in a very young universe, regions around supermassive black-holes and cosmic explosions like supernovae and highly energetic Gamma-ray bursts, faint dwarf galaxies and young and massive stars.

ARIES scientist Dr. Amitesh Omar had led the project to develop the spectrograph with a technical and scientific team. The team did the research and developed various optical, mechanical, and electronics subsystems of the spectrograph and camera. 

Various national institutes and organisations including the Indian Space Research Organization (ISRO) were involved in reviewing and developing parts of the instrument.

ARIES now plans to commission more complex instruments such as spectro-polarimeter and high spectral resolution spectrograph on the 3.6-m Devasthal telescope.

ARIES Director Prof. Dipankar Banerjee said that the indigenous efforts to build complex instruments like ADFOSC in India is an important step to become ‘Aatmanirbhar’ in the field of astronomy & astrophysics.”


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