Galactic Centre

The Galactic Centre (or Galactic Center) is the rotational center of the Milky Way galaxy. 
It is a supermassive black hole of 4,100 ± 0.034 million solar masses. It powers the compact radio source Sagittarius A*. 
It is away from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest.
Baade's window.
Walter Baade searched for the centre of the Milky Way galaxy in the mid-1940s. He used the Hooker telescope at Mount Wilson Observatory in California. 
Up until then the structure and position of the galactic center was not known for sure.
In 2006, the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) conducted a survey of 180,000 stars for seven days. The objective was to detect extrasolar planets by the transit method.
OGLE and other observation programs have successfully detected extrasolar planets orbiting around central bulge stars in this area by the gravitational microlensing method.