M 51

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 Largest Image (1.1 meg)
Description: Nicknamed 'The Whirlpool Galaxy', M51 has two asymmetric spiral arms, one of which appears to be interacting with NGC 5195, the smaller, golden, elliptical galaxy on the left. NGC5195 is, however, a background galaxy. These two galaxies have had close encounters in the past. The most recent encounter was some 70 million years ago. The prominent spiral arms of M51 are thought to be a result of these encounters. The current, strong star formation in these arms is the result of the gravitational collapse of gas shocked by the last encounter.
Constellation: Canes Venatici
Distance: 31-37 million light years (This is still a matter of study)
Apparent Size: 11' x 7'
Date: 11, 21, 25 march and 9 april 2007
Equipment: 12.5" RCOS RC @ f/9, ST10XME, AP1200
Exposure: LRGB: 3.3--2.7--2.2--3.7 hours, Astrodons unbinned