Spectrograph designed for Uttarakhand telescope
A team of scientists from the Aryabhatta Research Institute of observational sciences (ARIES), Nainital, with help from the Indian Space Research Organisation, have designed and developed a spectrograph, an instrument that separates incoming light by its wavelength or frequency and records the resulting spectrum.
The instrument will support the 3.6 metre Devasthal Optical Telescope (DOT) in Uttarakhand, an official release from the department of science said on Wednesday.
The instrument costs nearly ₹4 crores and has been named Aries-Devasthal Faint Object Spectrograph & Camera (ADFOSC), the release said. So far, such spectrographs were imported by the country and cost nearly 2.5 times more.
The instrument can detect faint light sources from distant quasars and galaxies, regions around supermassive black holes, and cosmic explosions and forms.
The instrument uses several lenses made of special glass that enable it to produce sharp images of the celestial objects, the release said. It can capture light sources with photon rate of less than one photon per second. A 100-watt bulb emits 10^20 photons in a second.
Now, ARIES plans to commission more complex instruments such as spectro-polarimeter and high spectral resolution spectrograph on the telescope, the release said.
Dr Amitesh Omar from the institute led this project with experts from various institutes including Isro.
“The indigenous efforts to build complex instruments like ADFOSC in India is an important step to become ‘Aatmanirbhar’ in the field of astronomy and astrophysics,” said professor Dipankar Banerjee, Director, ARIES.
A test set-up of the new instrument was used to study the Crab Pulsar, which is a relatively young neutron star (the collapsed core of supergiant stars), the release said.
Inaugurated in 2016, the 3.6 metre DOT is the largest fully-steerable optical telescope in Asia, which was built in collaboration with Belgium. However, it is of global importance as it fills in the twelve-hour longitudinal gap between 4m class telescopes located at Canary Island in the West and Australia in the East. The observation time on the telescope is shared 60% on competitive basis to astronomers in any Indian institution, 33% to astronomers from ARIES, Nainital, and 7% to Belgian astronomers.