Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 July 10
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

M51: Cosmic Whirlpool
Credit & Copyright: Tony and Daphne Hallas

Explanation: Follow the handle of the Big Dipper away from the dipper's bowl, until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you'll likely find this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. 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 (left), NGC 5195. The pair are about 37 million light-years distant and officially lie within the boundaries of the small constellation Canes Venatici. While M51 is visible as a faint, fuzzy patch in binoculars, this sharp color picture was made with a 14 inch telescope and combines digital camera exposures totaling 3 hours and 42 minutes.

Tomorrow's picture: tempest in a whirlpool

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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