Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194.
Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195.
The pair are about 31 million light-years distant and officially lie within the boundaries of the small constellation Canes Venatici.
Though href="http://www.seds.org/messier/more/m051_snhst.html">M51 looks faint and fuzzy in small, earthbound telescopes, this sharpest ever picture of M51 was made in January 2005 with the