'This does not look right': Scientists accidentally measure ultrahot ring around black hole using rare 'double zoom' technique

Woah. Using a telescope and a galaxy in between to enhance the image is a surprising way to see more detail around a black hole. 

It's a cool "trick" of using the corona edge to refract light.  

https://www.livescience.com/space/black-holes/astronomers-accidentally-use-rare-double-zoom-technique-to-view-black-holes-corona-in-unprecedented-detail