VIIRS Images of Ayodhya in India. 6th November 2020 on left, 13th November 2020 on right, showing the increase in brightness due to Diwali. Data processing courtesy of Earth Observation Group, NOAA/NGDC.
This week we’re returning to our infrequent blog series ‘Can this be seen from Space?’
Last weekend was Diwali and there was television coverage of the northern Indian city of Ayodhya, in the district of Uttar Pradesh, setting a Guinness World Record for the greatest number of oil lamps lit. It got us thinking whether the record attempt was visible from space?
Diwali, known as the festival lights, is celebrated by Hindus, Jains and Sikhs across the world, and symbolises the triumph of good over evil. It is celebrated in a variety of ways including the lighting of oil lamps known as ‘diyas’, which for many are to help the goddess Lakshmi find her way into peoples homes.
It was the lighting of diyas that caught our attention in Ayodhya last Friday evening, where 606,569 were lit by volunteers, following the first at Ram Ki Paidi ghat in the north of the city. The images of all these diyas were spectacular, and you can see some of the images here. This number was a Guinness World Record, beating the previous record of 409,000 that was also set in Ayodhya last year.
Of course, as the lamps were lit at night, optical imagery from Sentinel-2 or Landsat was not helpful. So we turned to the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership satellite, which collects both day and night-time images.
Google Earth image of city of Ayodhya, India. Image courtesy of Google and Maxar Technologies.
VIIRS is the best source of calibrated and georeferenced night-time imagery of the planet, although the astronauts on the International Space Station do take some stunning pictures. At night, VIIRS collects temperature data and the night-time imagery using the 750 m spatial resolution Day/Night Band (DNB).
We downloaded images from both the 6th and 13th November, which are shown at the top of this blog, and the additional brightness on the right image from the 13th November is clearly visible in comparison. Above is an image of Ayodyha from Google Earth with the Ram Ki Paidi ghat location identified by the blue pin.
Zoomed in VIIRS Images of Ayodhya in India. 13th November 2020, with Ram Ki Paidi ghat location shown. Data processing courtesy of Earth Observation Group, NOAA/NGDC.
To the right is a zoomed in section of VIIRS image at the top of the blog for the 13th November 2020, and the blue pin also indicates the location of Ram Ki Paidi ghat which demonstrates that the brightness is coming from the diyas.
So whilst on Earth the television cameras caught some amazing images, we have been able to answer the question ‘Was Diwali visible from space?’, and the answer is yes – at least the Diwali celebrations in Ayodhya were definitely visible form space in 2020!
