M101
Messier 101
Image Credit: NASA, ESA, CFHT, NOAO;
Acknowledgement – K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)
Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier’s famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way. M101 was also one of the original spiral nebulae observed by Lord Rosse’s large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic spans about 40,000 light-years across the central region of M101 in one of the highest definition spiral galaxy portraits ever released from Hubble. The sharp image shows stunning features of the galaxy’s face-on disk of stars and dust along with background galaxies, some visible right through M101 itself. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.
Tomorrow’s picture: Churyumov-Gerasimenko
M101
影像提供: NASA, ESA, CFHT, NOAO;
志谢 – K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu 朱有花 (U. Illinois)
说明: 庞大美丽的螺旋星系M101，是著名梅西耶星表所收录的最后一个天体，但这绝不代表它最不起眼。这个跨幅约170,000光年的庞大星系，大小几乎是我们银河系的2倍。在十九世纪罗斯伯爵使用帕森城大望远镜进行观测时，M101是透过此望远镜见到的首批”涡状星云”之一。上面这幅由哈勃太空望远镜团队所发布、涵盖M101中心约40,000光年区域的影像，除了组合哈勃望远镜在20和21世纪拍摄的51张照片之外，也整合了地基望远镜的影像数据，成为历年来记录螺旋星系的最高画质影像之一。这幅清晰的影像，无比清楚的呈现这个正向星系盘面恒星和尘埃所聚成的特征结构，以及后方的背景星系，有些甚至透过M101直接可见。亦名为风车星系的M101，位在北天的大熊座之内，离我们约有2千5百万光年远。
明日的图片: Churyumov-Gerasimenko
