Originally published in The Hindu Bangalore edition (City section) in July 2011.



Bangalore: It was only five years ago that Pavan Murthy, founding member of the Bangalore Astronomical Society (BAS) would take his fellow astronomy enthusiasts 40 kms from the city to Shivanahalli to observe the stars under a clear sky. Later, the group took their equipment to Hosahalli, which “also deteriorated,” he says.

Presently, the BAS and other amateur astronomers have to travel all the way to Kodagu, and “elsewhere in the Western Ghats” for their excursions, according to Mr. Murthy. A few decades ago these enthusiasts could have certainly stayed closer to city limits, but the increased amount of light pollution in the city has forced them to set up astronomical apparatus as far away from Bangalore as possible, or any other metro for that matter. The Jawarharlal Nehru Planetarium is unable to do much to help them either, since its telescope observatory is located under the light-polluted skies of Bangalore.

Light pollution is caused by large, wasteful amounts of artificial light from malls, advertising billboards, offices and street lamps. “The artificial light emitted is often thrown up into the sky when it should be restricted to lighting the area below,” says Dr. B.S Shylaja, deputy director at the planetarium. Light pollution diminishes the brightness of celestial objects in the sky. Light pollution “may not directly affect human health, but plant life and insect life cycles have been impacted,” says Dr. Shylaja adding that aviary life too has been affected by the lighting put up at Lal Bagh and Cubbon Park.

The Jawarharlal Nehru Planetarium was set up in 1989. It has telescopic and observatory equipment worth lakhs for sky-gazing, but its utility has dimished due to light pollution. C.S Shukre, the director at the Planetarium says that observatories set up within a city were “never intended to be ideal for ‘serious’ astronomy”, but admits that apart from the sun, moon and nearby stars and planets, “faint celestial objects that were previously visible are now completely out of our range.”

Mr. Murthy adds that “popular constellations” such as Orion, Scorpius and Big dipper are “still visible”, but more obscure ones such as Leo and Andromeda are less visible since “the naked eye limiting magnitude (of stars) in Bangalore has reduced from being 4 or 5 to approximately 3 or 2.5.” But does this mean the telescope observatory would have shift elsewhere in the near future, due to the uncontrolled amount of light pollution? “Limitations of astronomy in a city continue to exist, but all forms of pollution will always exist in a city,” says Mr. Shukre, saying that even air pollution – the lack of clear air due to unahealthy amounts of dust and carbon in the air – is an “urban contribution that hinders our observation.”

Among the world’s cities, metros such as New York, Las Vegas, Tokyo, London and Berlin are among the most light-polluted, according to satellite map images released by NASA. Within India, New Delhi, Mumbai, Kolkata, Chennai, Hyderabad and Bangalore appear the brightest from space. More recent images show that emerging cities such as Gurgaon, Surat, Ahmedabad and Vadodara have been emitting large amounts of artificial light.

In a plea to reduce light pollution, Dr. Shylaja told Karnataka Power Transmission Corporation that of light being thrown upwards in street lamps should be modified so that all light is emitted only downward with the help of a down-facing hood around the lamps. Mr. Shukre, however says that “we must study the source (of light pollution) based on type, area and quantity” before tackling measures are drawn up.