In recent years we witnessed tremendous progress in high frequency very long baseline radiointerferometry (VLBI). These developments were most notably marked by the first image of a supermassive black hole (and a first VLBI image in 230 GHz frequency), obtained by the Event Horizon Telescope. The near future will bring further technical improvements, enabling more detailed studies of astrophysics of accretion and of general relativity. I will discuss some of those anticipated improvements, highlighting the possibility of probing the photon ring structure of the M87, and studies of the accretion dynamics from multi-epoch observations.

Maciek Wielgus received bachelor degree in mathematics from Warsaw University and master degree in photonic engineering from Warsaw University of Technology in 2010. He obtained a PhD degree from Warsaw University of Technology in 2016 for the work on adaptive analysis of interferometric fringe patterns. Since 2017 he is a Black Hole Initiative Postdoctoral Fellow at Harvard University. As a part of the EHT team he was awarded the Breakthrough Prize in Physics in 2020 for the observations of the supermassive black hole in the center of M87. Maciek is currently serving as a Time Domain working group coordinator for the EHT.