Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.
Sign up to join this community
In The Prisoner of Azkaban movie Harry and Hermione used Time-Turner to save Sirius. After advising them to use Time-Turner Dumbledore remind them "you must not be seen". If it was a vital law to use Time-Turner, why didn't they just use the invisibility cloak to hide themselves while they were on time travel?
PS: I haven't read the book yet.
They don’t have it with them.
In the books, the Invisibility Cloak gets dropped at the base of the Whomping Willow. Snape picks it up, and uses it to sneak up on the people in the Shrieking Shack:
“I found this at the base of the Whomping Willow,” said Snape, throwing the cloak aside, careful to keep this wand pointing directly at Lupin’s chest. “Very useful, Potter, I thank you….”
— Chapter 19 (The Servant of Lord Voldemort)
In all the kerfuffle with Pettigrew, nobody picks up the Cloak to bring back to Hogwarts. Instead, it gets returned by Lupin as he’s packing to leave:
“Here — I brought this from the Shrieking Shack last night,” he said, handing Harry back the Invisibility Cloak.
— Chapter 22 (Owl Post Again)
I don’t have the films to hand, so I can’t remember if/how this is addressed in the film canon.
When they were able to hide multiple people under it, they were much younger and shorter, even then it was still difficult to move while they were all still hidden. At the point of saving Sirius the cloak might not have been able to cover more than one person, and would have made moving very slow and cumbersome.
Further, Hermione was seen when she was using the time turner to take multiple classes. I don't think not being seen is critical for the time turner itself, I think not being seen at a time/place you shouldn't be, or being seen by your past self who doesn't have knowledge of the turner is critical.
