NGC 6572
planetary nebula
NGC 6572 is a planetary nebula in the constellation Ophiuchus. It was discovered in 1825 by the German astronomer Friedrich Georg Wilhelm von Struve. According to several sources such as Sky & Telescope, this object received the nicknames Blue Racquetball, Emerald Nebula, Green Nebula, and Turquoise Orb. At magnitude 8.1, NGC 6572 is easily bright enough to make it an appealing target for amateur astronomers with telescopes. At low magnification, it will appear to be just a colored star, but…