In the early morning darkness, Devendran P. walks up a hill to a solar observatory in the southern hill town of Kodaikanal, trudging the same path his father and grandfather walked in a century-old family tradition of studying the sun.
Once inside, he pulls a rope to open shutters in the dome and positions a six-inch telescope used since 1899 to photograph the sun and preserve a daily record of its activity.
"The sun, like stars, has a lifetime of 10 billion years," Devendran said. "If you want to know about any small changes, you need to have a large amount of data."
The observatory, run by the Indian Institute of Astrophysics, has a key role in providing a continuous stream of data on the sun and its influence on Earth and surrounding space, said R. Ramesh, a professor at the institute.
"Some of the discoveries made, based on data obtained in the Kodaikanal observatory, are so fundamental to solar physics that they vastly improved techniques used at observatories even today," Ramesh said.
In the observatory library, shelves stretch to the ceiling, packed with volumes of handwritten records and thousands of film plates of the sun. Authorities have launched a project to digitise and preserve the data collected over the past century.
Devendran's grandfather, Parthasarathy, joined the observatory in 1900, a year after it relocated from Chennai, the state capital, to Kodaikanal, situated more than 6,562 feet above sea level, offering ideal weather to study the sun.
Like his father and grandfather, Devendran has no formal education in astronomy. His interest was piqued during a visit to the observatory when he was a child.
He became a fulltime sun watcher in 1986 and says the six-inch ( telescope has never failed his family.
"It has never required any major overhaul, or change of parts, because we all take care of it," he said.
His 23-year-old son, Rajesh, expects to carry on the family tradition, but with one difference. He has a master's degree in physics.
"I get amazed by what my father does here," said Rajesh. "I think observing the Sun is in my blood."