 Globular star cluster NGC 6397 is one of the oldest objects in the universe. It's estimated to be 13.4 billion years old. It's also one of the closest such star systems to Earth. In 2018, using the new spatial scanning-based parallax data, astronomers have, for the first time, precisely measured the distance to this globular cluster. The new measurement sets the cluster distance at 7,800 light years, with just a 3% margin of error. This is significantly better than the Hertzsprung-Russell diagram technique based on luminosities and star colors. The margin of error for HR diagram estimates range from 10 to 20%.