How to take a picture of a black hole

Astronomers are preparing to take the first ever picture of the boundary of a black hole - its "event horizon".

The Event Horizon Telescope is set to deliver a portrait of Sagittarius A*, at the centre of the Milky Way, in early 2017.

Prof Feryal Ozel from the University of Arizona spoke to science reporter Jonathan Webb about the project - and gave her thoughts on the black hole special effects we know from films like Interstellar.