#OTD 2006: Astronomers announced that they'd used Hubble to find the dimmest stars yet seen in any globular star cluster. This cluster, NGC 6397, formed early in the universe's history and is one of the closest clusters to Earth: https://t.co/YoyxlHJS5Z pic.twitter.com/ARhwZ1XkHK

— Hubble (@NASAHubble) August 17, 2018