The angular resolution is mind-blowing. Combining these telescopes gives us resolutions on the order of the orbit of Mercury around the sun, at a range of our distance from the center of the galaxy. If the Earth were the size of our eyes, it would be like seeing objects of diameter 11.5 meters (37.7 feet) from about 7622 km (4736 mi) away. Almost like seeing a small apartment building in London from Los Angeles, with the naked eye.

> The increased angular resolution provided by the APEX telescope now reveals details in the asymmetric and not point-like source structure, which are as small as 36 million km. This corresponds to dimensions that are only 3 times larger than the hypothetical size of the black hole (3 Schwarzschild radii).

> “It reveals details in the central radio source which are smaller than the expected size of the accretion disk”, adds Thomas Krichbaum, initiator of the mm-VLBI observations with APEX.

Synthesizing with Wikipedia:

> The current highest-resolution measurement, made at a wavelength of 1.3 mm, indicated an angular diameter for the source of 37 μas.[12] At a distance of 26,000 light-years, this yields a diameter of 44 million kilometers. For comparison, Earth is 150 million kilometers from the Sun, and Mercury is 46 million kilometers from the Sun at perihelion. The proper motion of Sgr A* is approximately −2.70 mas per year for the right ascension and −5.6 mas per year for the declination.[13][0]

[0] https://en.wikipedia.org/wiki/Sagittarius_A*

Diameter

  Earth 12,756,000 m
  Eye   0.025 m
  Ratio 510240000x