NGC 6397 is a globular cluster in Ara. It contains approximately 400,000 stars and is located around 7800 light years from here.
Most of the cluster’s blue stars are near the end of their lives and have used up their hydrogen fuel. These stars are now converting helium to energy in their cores. This fuses at a higher temperature and creates a blue color.
There are many red giant stars that have consumed their hydrogen fuel and have expanded in size and numerous yellow and white stars some similar to our sun.
Imaged in LRGB on our RiDK 400 at Observatorio El Sauce, Chile.
Image Processing: Mike Selby