Click on the image for a full resolution version   Messier 54 is a special globular cluster. It hosts about 1 Million stars, has a luminosity of 850,000 suns and has a total mass of 1.5 Million solar masses. It is located at 87,400 light years in the constellation Sagittarius. Discovered in 1778 by Charles … Continue reading Messier 54. NGC 6715