A British professor has been reported missing while on a research trip to Chile, police have said.
Tom Marsh, 60, from Rugby in Warwickshire, had been visiting La Silla Observatory on the outskirts of the Chilean Atacama Desert, about 370 miles (595km) north of capital Santiago.
He has not been heard from since the night of Friday 16 September.
Police described him as white, about 6ft 3in tall, balding, with grey hair and a beard.
He is likely to be wearing a blue rain jacket, walking boots and a grey woollen hat.
Professor Marsh works in the Department of Physics at Warwick University, where his research interest is in binary stars.
In a statement through Warwickshire Police, his family said: "We are deeply concerned for Tom and miss him, and would ask anyone who may any have information on his whereabouts to please help."
In a post on social media, his daughter Tabitha said the family was "desperate" to find him, adding: "He was out on an observing run at the La Silla Observatory in Chile when he went missing.
"The closest town is La Serena. If anyone has any information or thinks they can help in any way, please contact the police... Thank you.
"My family, and my dad's friends and colleagues, would be beyond grateful for any help or information."
Warwickshire Police said its officers are in contact with the Foreign Commonwealth and Development Office and Interpol, as well as Chilean authorities.
Anyone with information should call Warwickshire Police on 101 quoting incident number 153 of 18 September 2022.
If calling from outside the UK, police can be contacted on +44 1926 415000 or information can be reported online.