THE passage of time is perhaps not so acute to the centuries-old alien at the heart of the BBC’s “Doctor Who,” the shape-shifting hero known simply as the Doctor, who has had more than 50 years of adventures across dimensions known and otherwise.

But time and its measurement have become especially crucial to Peter Capaldi, who will make his proper, full-length debut as the latest actor to play the Doctor when the new season of “Doctor Who” has its premiere Saturday on BBC America.

It has been just over a year since the BBC announced that Mr. Capaldi would succeed Matt Smith, who was a 26-year-old relative novice when he was chosen to play the Doctor, and, after three seasons of putting his frantic, whirling-dervish stamp on the character, disclosed his departure in June 2013.

Since then, Mr. Capaldi, 56, has spent several months filming “Doctor Who” in Cardiff, Wales, trying to bring to the role his own personal take, which he says is more sardonic and elusive.