How does interferometry work?

NRAO: interferometry
Black holes are so so tiny on the sky that any effort to image a black hole requires a team of telescopes, all working together, using a technique called interferometry. This graphic from the National Radio Astronomy Observatory (NRAO) explains interferometry and how collaborations like the EHT use it observe black holes.

The Shape of A Black Hole Shadow

EHT infographic showing a simulation of a black hole
This infographic shows a simulation of the outflow (bright red) from a black hole and the accretion disk around it, with simulated images of the three potential shapes of the event horizon’s shadow. Credit: ESO/N. Bartmann/A. Broderick/C.K. Chan/D. Psaltis/F. Ozel

The Anatomy of a Black Hole Accretion System

Infographic labelling the parts of a black hole
This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion. Credit: ESO, ESA/Hubble, M. Kornmesser/N. Bartmann

Katie Peek: Light's Odyssey

Comic strip showing path of light from edge of black hole to EHT
Artist Katie Peek created the below comic strip to accompany the article "Resolved magnetic-field structure and variability near the event horizon of Sagittarius A*", published in Science in December 2015.