"Whirlpool Galaxy"
The Whirlpool Galaxy, also known as Messier 51a, M51a, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus.[7][6][8] It lies in the constellation Canes Venatici,and was the first galaxy to be classified as a spiral galaxy.[9] Its distance is estimated to be 23 millionlight-years away from Earth.The galaxy and its companion, NGC 5195,[10] are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars.[11] The Whirlpool Galaxy has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.