I made this video using a series of jpeg’s output from the Aladin astronomy sky and catalogue visualization software, ffmpeg, and a handy github script. At optical wavelengths the nebula is dark except at the rim. Gradually more stars are revealed, with young stars most deeply embedded in the cloud showing up at longer wavelengths. Finally, far-infrared Herschel imaging shows one, dominant source which may be the earliest phase of star formation we can see here. The different wavelengths correspond to different temperatures, which can be found using this calculator. Near- and infrared images are from 2MASS (ground) and Spitzer (space) respectively.