In May 2018, the star S2 made its closest approach to the black hole at the centre of the Milky Way. Observing this event was no easy task. The centre is full of dense dust clouds, impenetrable at visual wavelengths. The unique instruments GRAVITY and SINFONI, able to take highly precise measurements, needed to be developed for these observations. Frank Eisenhauer, a member of the Galactic Centre group at Max Planck Institute for Extraterrestrial Physics and principal investigator for GRAVITY and SINFONI, talks about observing the close approach of S2 in the second of a three blog post series.