Astronomy Picture of the Day . ... Perhaps the original spiral nebula , the large galaxy with well defined spiral structure is also cataloged as NGC 5194a. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (left), NGC 5195 . ... Though M51 looks faint and fuzzy to the human eye, the above long-exposure, deep-field image taken last month shows much of the faint complexity that actually surrounds the smaller galaxy. ... Publications with keywords: M 51 - Whirlpool galaxy . ...