Pollution down, sky clearer: Amateur astronomers have a good time
Amateur astronomers in cities across India are making the best out of a bad situation to observe celestial objects --stars, constellations and planets -- in skies that have become unusually clear because of reduced pollution after the all-India lockdown came into force on March 25 to stop the spread of the coronavirus (Covid-19).
The night skies, especially, have brightened with many more stars visible, according to astrophysicists in Kolkata who are monitoring celestial events with a telescope.
“The stars, which were earlier only eight times brighter compared to the black sky in the background, have become at least 13 times brighter now compared to the black background. With the help of our telescopes we can now observe stars which were at least three times fainter earlier,” said Sandip K Chakrabarti, director of Indian Centre for Space Physics (ICSP) and former head of the astrophysics and cosmology department at the SN Bose National Centre for Basic Sciences.
HT reported on March 24 a general improvement in air quality across the world amid lockdowns to check the spread of Covid-19. The European Space Agency (ESA) has released satellite images showing a plunge in nitrogen dioxide (NO2) levels. In India, the government has cancelled flights and trains and taken public transport off the roads.
“Constellations such as the Orion, Auriga, Gemini and Canis Minor have become much brighter now. One can see these constellations much clearly because of the drop in air pollution levels,” said Basudev Bhattacharya, president ofthe Sky Watchers’ Association in Kolkata.
The concentration of aerosols that used to scatter light and create a dense haze have dropped because of the lockdown. An analysis by the Centre for Science and Environment in Delhi has revealed that morning and evening peaks in PM 2.5 (particulate matter 2.5, fine, respirable pollution particles) levels have flattened out.
“As a result of this, several stars and planets have become much brighter. The Canopus star in the southern hemisphere is looking quite bright. Planets such as Jupiter, Mars and Saturn have become brighter and can be seen before dawn around 4 am. Venus is also looking brighter in the evening sky,” said J Khemchandani, secretary of Ahmedabad’s astronomy club.
“The sky is now dotted with stars, many of which were earlier not visible. Earlier, only two objects from the deep sky were visible. But now I can see at least five including the Little Beehive star cluster, Messier 36, Messier 37 and Messier 38. These could be seen in the western sky in the evening. Earlier I could see only two to three stars of the Scorpio constellation. But now I can see the entire constellation. Even the pole star is shining brightly over the last one week or so,” said Sneh Kesari, an amateur astronomer in Delhi.