It's one of the most famous stories in the literary field: how Mary Shelley woke up from a dream to write the iconic "Frankenstein". Now a group of astronomers have proved that the author's account of how the moon shone through the window of her room in Villa Diodati is actually true.

Donald Olson, an astronomy professor at Texas State University in San Marcos told Reuters on Monday that the night sky during that time would show that Shelley was telling the truth about the birth of Frankenstein.

"Some scholars are very skeptical, they even call her a liar," Olson said. "But we see no reason, either in the science or in the primary sources, to doubt Mary Shelley's account."

Shelley, her husband poet Percy Shelly, Lord Byron and John Polidori were all staying at the Villa Donati in Switzerland in June of 1816 when the group proposed that they each write a horror story. The result was the Mary Shelley's "Frankenstein".

Shelley famously said she saw a "bright and shining moon" through her window and wrote Frankenstein during a "waking dream". Critics have said this was merely a way for her to sell the book by adding Gothic embellishments.

"Shelley gave a very detailed account of that summer in the introduction to an early edition of Frankenstein, but was she telling the truth?" Olson said. "Was she honest when she told her story of that summer and how she came up with the idea, and the sequence of events?"

"Shelley gave a very detailed account of that summer in the introduction to an early edition of Frankenstein, but was she telling the truth?" Olson said. "Was she honest when she told her story of that summer and how she came up with the idea, and the sequence of events?"

Olson along with fellow astronomy professor Russell Doescher, English professor Marilyn S. Olson and Honor Program students Ava G. Pope and Kelly D. Schnarr set out to prove if Shelley's account was right. Olson and his team made topographic measurements of the terrain of Villa Diodati and investigate the weather records for June of 1816.

On the night in question the team determined that it was possible for Shelley to see the bright, gibbous moon through her window just before 2 am on June 16. If there had been no moonlight visible that morning, Shelley would have made-up her account.

"This indicates her famous "waking dream" that gave birth to Frankenstein's famous monster occurred between 2 a.m. and 3 a.m. on June 16," he said. The team will publish their findings in the November edition of Sky and Telescope Magazine.