That Unforgettable Visit to Vainu Bappu Observatory

-A Nitiya Naren X-B

It was a Saturday afternoon, and the sun was hiding behind the cloudy, overcast sky. We were in a car, driving through the hills. It was green as far as the eye could see. The place was full of trees and shrubs, all aligned like plantations on a gentle slope. Sometime later came a blue gate, ending the thrilling four-hour journey through steep hills, and we parked the car beside it. And then reality struck me, there we are, at the Vainu Bappu Observatory.

Ever since I knew there was such a place near the city of Vellore in Tamil Nadu, I wanted to visit it. I used to imagine being there, in a serene, peaceful place, with almost no people around, no buildings around, no fuzzy lights and vehicles around, and the night sky lit with thousands of stars twinkling brightly. Amidst all this is the giant telescope that scans the night sky for celestial objects and interesting space phenomena. It was truly the place of my dreams.

And on the day when one of my dreams came true, I was rendered speechless. As I went inside, my stomach seemed to be filled with butterflies, and my eyes started searching for telescopes, though none were in sight. But reality shouted in my mind, “Wait! You still have work to do.” We bought entry tickets requiring a nominal fee of Rs. 50 per person and then went to the visitors’ waiting area to wait there till 20 or so people would come for the first batch. Every Saturday from 2 PM to 5 PM, people are taken to the primary telescope in batches to explain the functions of the telescope, what discoveries and observations take place, and various other things about our Universe. If people were lucky enough and the night sky on that day was clear, then a small telescope would be used for night sky observations by the visitors. As time passed by, it was very difficult for me to control my excitement.

The Primary Telescope is the Vainu Bappu Telescope, one of the largest telescopes in Asia. It has a 2.3 m primary mirror that captures the image and reflects it into the instruments to obtain valuable data. The telescope is so powerful that it can even resolve a 25 paise coin kept 40 km away. It is primarily used for Spectroscopy, a method used to study celestial objects in light bands. We all know that light is not one single ray, but is made up of several colours of rays. Along with those 7 colours that make up the visible light spectrum, there are several other spectra in the light spectrum with various energy levels. The instruments simply interpret the images captured by the mirror and return them in absorption and emission spectra, which are then interpreted into different conclusions by scientists and astronomers. This telescope was fully manufactured in India in 1986 by the Indian Institute of Astrophysics, with a few pieces of equipment imported.

Another main telescope used there is the JC Bhattacharya Telescope. It has a primary mirror of 1.3 m and is used for photometry, which is to click pictures and create images of celestial bodies for research.

The interesting thing about this observatory is that the 1 m Carl Zeiss telescope is associated with two major discoveries, one being the discovery of an atmosphere around Jupiter’s Moon Ganymede in 1972 and the second being the discovery of rings around Uranus in 1977.

After we waited for a brief amount of time, we were taken to the telescope. We had to walk a long, sloped road for almost 1 or 2 kilometres before reaching the telescope. As I walked up that slope, my excitement increased, but so did my impatience. The road just seemed to stretch endlessly ahead. On the way were the other telescopes, standing majestically and facing the vast cosmos. But all this effort was worth it. The telescope building had three floors. What I expected was machinery inside a cramped, small room. But I was wrong.

As I got out of the elevator, I realised how big this structure was. The circular floor enclosed by a dome would have easily engulfed a spacious three-bedroom flat that had massive balconies on either side. And the telescope rested on a massive structure that was supported by two concrete bases as tall as a fully grown elephant. A colossal three-beam mount held the telescope with its primary mirror, secondary mirror, and instruments in place, and it ended in a circular enclosure that rotated on oil pads to smoothly change the location at which the telescope would focus in the sky. Its size and grandeur humbled me because I seemed like an ant standing between these giant marvels of engineering. And as I drowned in this serene and humbling feeling, a person called me from what seemed to be a thousand kilometres away and told me to take a seat.

I took a seat on the floor that had a carpet on it with my parents, while my grandmother was sitting on a chair. The person who called me was a scientist working there, as part of the Indian Institute of Astrophysics, the institute operating this whole observatory. He explained about this telescope, its workings, its functions, the instruments on board, and the various other regions where telescopes like this were built. He also explained various physical phenomena taking place in the Universe and briefed us about different celestial bodies. But then something unexpected happened.

The speaker instructed two men standing behind him to start and told us to look up. The control room behind me, with people burying their faces into the thousands of buttons, sticks, and keys, suddenly did something that I’ll never forget. The two majestic shutters of the dome, with a slight whining noise, opened smoothly, revealing the vast, grey, cloudy, and overcast sky. From this frame of reference, the sky looked absolutely massive and high. It was magical. Then, the mount moved on the oil pads, moving the telescope towards its target position.

This telescope contained an equatorial mount, a mount that is calibrated to match the Earth’s rotational axis. It only moves on one axis in an East to West direction on the oil pads. The telescope assembly then moves north and south to get to its target position. The other type of mount is the altazimuth mount. This mount operates on two axes, one in a north-south direction and the other in an east-west direction. But controlling this mount requires precision and computers, which weren’t available at the time of this telescope’s inception, in 1986. Hence, the equatorial mount was chosen and operated using analogue controls.

The telescope and mount were then moved to their resting positions, and the shutter closed, but that image of the sky in my mind didn’t. This came as a big surprise to me. I never thought that the team at the observatory would show us a working demo of the telescope’s operation. It was spectacular! After that, I headed back, with those two telescope shutters still open in my mind. Unfortunately, I wasn’t able to watch the night sky there as the weather was overcast. But if I had, it would have been fantastic, as I would have been able to see thousands of stars and even a faint view of the Milky Way galaxy. But that’s for another day.

For a person who has just seen telescopes in Discovery Science and Google Images, this experience was one worth remembering for a lifetime. It further enhanced my interest in space, science and technology and gave me a stronger case to explore it more. There are many more observatories like this across India, and this gave me the urge to visit them all. But this experience was truly unforgettable!