Astronomy Picture of the Day . The Last Moon Shot . ... NGC 6888, also known as the Crescent Nebula, is a cosmic bubble of interstellar gas about 25 light-years across. Created by winds from the bright, massive star seen near the center of this composite image, the shocked filaments of gas glowing at optical wavelengths are represented in green and yellowish hues. ... Iridescent Clouds Over Aiguille de la Tsa . ... The Coma Cluster of Galaxies . ... Is the Moon larger when near the horizon? ...