A Virtual Observatory (VO) is not a physical instrument but a web-based research environment that allows astronomers to "interrogate" vast archives of astrophysical data.

The most powerful "virtual telescopes" are created through . By synchronizing multiple radio telescopes across continents, scientists create a virtual dish as large as the distance between them.

A "virtual telescope" is a versatile concept in modern astronomy, ranging from global networks of physical observatories to software-based simulations and data archives. This write-up explores the three primary definitions of virtual telescopes and their impact on scientific discovery. 1. The Global Network: Earth-Sized Observatories

In 2019, the EHT collaboration captured the first direct image of a black hole in the M87 galaxy, a feat requiring magnification equivalent to reading a text on a phone in New York from a sidewalk café in Paris.

This is the most famous example, linking eight observatories on four continents to form a single Earth-sized virtual telescope .