In a recent blog post within the series entitled "Taking the First Picture of a Black Hole", the ESO outreach team explains some technological challenges that the Event Horizon Telescope collaboration faces in pursuit of high-resolution images of black holes using the technique of very long baseline interferometry: Challenges in Obtaining an Image of a Supermassive Black Hole
"After completing five nights of observations, today astronomers may finally have captured the first-ever image of the famous gravitational sinkhole known as a black hole. [...]
As the final observing run ended at 11:22 a.m. ET, team member Vincent Fish sat contentedly in his office at the MIT Haystack Observatory in Westford, Massachusetts. For the past week, Fish had been on call 24/7, sleeping fitfully with his cell phone next to him, the ringer set loud."
"Soon ALMA will take on perhaps the most ambitious endeavor of its brief existence. Over 10 days in early April, it will join radio telescopes at five other sites spanning the globe, from Hawaii to the South Pole, in an attempt to capture the shadow of a supermassive black hole that sits at the heart of our Milky Way galaxy, and an even bigger one in the neighboring galaxy M87."
"...[A]n ambitious radio astronomy project now aims at taking the first snapshot of an actual black hole. In other words, a real-life picture of Interstellar’s black hole Gargantua, if a highly pixelated one."
"Ever since first mentioned by Jon Michell in a letter to the Royal Society in 1783, black holes have captured the imagination of scientists, writers, filmmakers and other artists. Perhaps part of the allure is that these enigmatic objects have never actually been “seen”. But this could now be about to change as an international team of astronomers is connecting a number of telescopes on Earth in the hope of making the first ever image of a black hole."
"The Milky Way’s great black hole is 25,000 light years distant, surrounded by dense clusters of stars, shrouded by interstellar dust and, like all other black holes, incapable of emitting light.
Yet scientists believe they will soon be able to take a photograph of this interstellar behemoth – an extraordinarily ambitious feat that will involve the creation of a radio telescope that has the effective size of our entire planet and whose operation will involve scientists from four continents."