Click on the image for a full resolution image Messier 7, the so called Ptolemy’s Cluster, was already known to ancient Greeks. Ptolemy described it without doubt. It has been catalogued by many astronomers, including Charles Messier, Edmund Halley and Nicolas Louis de Lacaille. This is the Southernmost Messier object. This is a large cluster, … Continue reading Messier 7. NGC 6745. Ptolemy’s Cluster