Question: What kind of telescope was used to get pictures of the black hole?

Event Horizon Telescope



The Event Horizon Telescope (EHT) is a project to create a large telescope array consisting of a global network of radio telescopes and combining data from several very-long-baseline interferometry (VLBI) stations around the Earth. The aim is to observe the immediate environment of the supermassive black hole Sagittarius A* at the center of the Milky Way, as well as the even larger black hole in the supergiant elliptical galaxy Messier 87, with angular resolution comparable to the black hole's event horizon.[1][2][3][4][5]
The current director of the project is Dr. Sheperd Doeleman. The main project scientist is Dimitrios Psaltis. The current project manager is Remo Tilanus. [6]
Overview
The EHT is composed of many radio observatories or radio telescope facilities around the world to produce a high-sensitivity, high-angular-resolution telescope.  Through the technique of very-long-baseline interferometry (VLBI), many independent radio antennae separated by hundreds or thousands of miles can be used in concert to create a "virtual" telescope with an effective diameter of the entire planet.[7] The effort includes development and deployment of submillimeter dual polarization receivers, highly stable frequency standards to enable very-long-baseline interferometry at 230–450GHz, higher-bandwidth VLBI backends and recorders, as well as commissioning of new submillimeter VLBI sites.[8]
Each year since its first data capture in 2006, the EHT array has moved to add more observatories to its global network of radio telescopes. The first image of the Milky Way's supermassive black hole, Sagittarius A*, was expected to be produced in April 2017,[9][10] but owing to the South Pole Telescope being closed during winter (April to October) the data shipment delayed the processing to December 2017, when the shipment arrived.[11] A date for the release of the image has not yet been announced. The image will also test Albert Einstein's general theory of relativity at the extreme.[7][10]
Data collected on hard drives must be transported by jet airliner (a so-called sneakernet) from the various telescopes to the MIT Haystack Observatory in Massachusetts, USA, and the Max Planck Institute for Radio Astronomy, Bonn, Germany, where the data are cross-correlated and analyzed on a grid computer made from about 800 CPUs all connected through a 40 Gbit/s network.[12]
Contributing institutions


Some contributing institutions are:[14]

ALMA
APEX
Academia Sinica Institute of Astronomy and Astrophysics
Arizona Radio Observatory, University of Arizona
Caltech Submillimeter Observatory
Combined Array for Research in Millimeter-wave Astronomy
European Southern Observatory
Georgia State University
Goethe-Universität Frankfurt am Main
Greenland Telescope
Harvard–Smithsonian Center for Astrophysics
Haystack Observatory, MIT
Institut de Radio Astronomie Millimetrique
Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)
East Asian Observatory – James Clerk Maxwell Telescope
Large Millimeter Telescope
Max Planck Institut für Radioastronomie
National Astronomical Observatory of Japan
National Science Foundation
National Radio Astronomy Observatory
University of Massachusetts, Amherst
Onsala Space Observatory
Perimeter Institute
Radio Astronomy Laboratory, UC Berkeley
University of California, Berkeley (RAL)
Radboud University Nijmegen
Shanghai Astronomical Observatory (SHAO)
Submillimeter Array (SMA)
Universidad de Concepción
Universidad Nacional Autónoma de México (UNAM)
University of Chicago (South Pole Telescope)
University of Illinois Urbana-Champaign
University of Michigan



Further reading
Non-technical:  (2001), Fulvio Melia (Princeton University Press), ISBN0691095051
Technical:  (2008), Fulvio Melia (Princeton University Press), ASIN


, New York Times video 2015