It’s after 10 on a Saturday night and I’m outside, near a soaking wet pebble beach on the Sussex coast. Most sensible people are safely indoors, but I’m trying to shelter from the rain behind a giant telescope. There is some comfort, however, because I’m sharing this surreal moment with a distinguished cast, one that includes Tony Blair, Russell Crowe and Obi-Wan Kenobi from Star Wars.

That all three voices are coming from the lips of one man doesn’t make the experience any less bizarre. Impressionist Jon Culshaw has been mimicking famous people since an early job on a radio station in Preston, Lancashire, when he would sometimes read the weather reports in the voice of boxer Frank Bruno. In 1994, he joined the team at Spitting Image, and later Radio 4’s Dead Ringers. However, long before he mastered Bruno’s laugh, Culshaw was finding his way around another star-studded universe, as an amateur astronomer.

As the skies above Culshaw’s London flat are often blighted by light pollution, we’ve arranged to meet in Selsey, West Sussex, at the home of The Sky at Night presenter Pete Lawrence, who seems to hoard telescopes like some people collect objets d’art. His house is within a pebble’s throw of the sea and so our plan is to spend the evening on the beach in a celestial huddle. My own Meade telescope has been gathering dust for years, but I’m hoping Culshaw, or one of his many characters, might inspire me to gaze at the heavens more often.