The technique, which has already unearthed stars, allows scientists to see what is invisible.
The newly-discovered black hole, which researchers have called LB-1, is located 15,000 light-years from Earth and so far scientists have only known of black holes with masses below 50 times that of the sun.
If, as researchers believe, the 2l/Borisov comet comes from another galaxy this makes it a huge discovery: as the first comet from so far away and the second object from intergalactic space observed in the Solar System.
The team from the University of Warsaw say their unique map, which was based on observing 2,400 stars less than 250 million years old, is more accurate than models currently in use.
What started off as a hobby 15 years ago, last month turned into a fulltime business for the enthusiast.
Named by the Polish astronomers who found them, the planets could be just two of millions floating through the galaxy. So far, though, scientists have only managed to locate a dozen or so rogues, which is why adding these two to the bunch is deemed important.