M51：哈勃的涡状星系影像
M51: The Whirlpool Galaxy from Hubble
Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Bernard Miller
Explanation: The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The featured image is a digital combination of images taken in different colors by the Earth-orbiting Hubble Space Telescope, highlighting many sharp features. Anyone with a good pair of binoculars, however, can see this Whirlpool toward the constellation of the Hunting Dogs (Canes Venatici). M51 is a spiral galaxy of type Sc and is the dominant member of a whole group of galaxies. Astronomers speculate that M51’s spiral structure is primarily due to its gravitational interaction with the smaller galaxy on the image left.
Tomorrow’s picture: pinnacle satellites
M51：哈勃的涡状星系影像
影像提供: NASA, ESA, Hubble, HLA; 影像处理与版权: Bernard Miller
说明: 涡状星系是个经典的螺旋星系。离我们只有3千万光年远、宽为6万光年、亦称为NGC 5194的M51，是天空最明亮最美丽的星系之一。上面这幅主题影像，是由地球轨道上的哈勃太空望远镜摄于不同颜色波段的照片数位组合而成，以突显数个不同的特征。不过，任何拥有一具好双筒望远镜的观星者，都应能在北天的猎犬座方向见到这个涡旋状的美丽星系。M51的分类为Sc型螺旋星系，也是它所在的星系团最庞大之成员星系。天文学家认为M51的螺旋结构，主要是它与位在影像左侧的小星系重力互扰下的产物。
明日的图片: pinnacle satellites
