Seven Sisters versus California
Image Credit & Copyright: Neven Krcmarek
Explanation: On the upper right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across. Surrounding the stars is a spectacular blue reflection nebula made of fine dust. A common legend is that one of the brighter stars faded since the cluster was named. On the lower left, shining in red, is the California Nebula. Named for its shape, the California Nebula is much dimmer and hence harder to see than the Pleiades. Also known as NGC 1499, this mass of red glowing hydrogen gas is about 1,500 light years away. Although about 25 full moons could fit between them, the featured wide angle, deep field image composite has captured them both. A careful inspection of the deep image will also reveal the star forming region IC 348 and the molecular cloud LBN 777 (the Baby Eagle Nebula).
Tomorrow’s picture: far star
七姐妹与加州星云
影像提供与版权: Neven Krcmarek
说明: 右上角带着蓝晕的天体是昴宿星团。亦名为七姐妹星团及M45的昴宿星团，也是天空中最明亮最容易辨识的疏散星团。位在400光年远之处的昴宿星团，其3000多颗成员星分布在宽只有13光年的区域里。这团恒星的周围，更环拱着由尘埃组成的壮丽泛蓝反射星云。一则传说如是说：在此星团获得七姐妹之名后，其中的亮星之一方才暗去。这幅影像左下方的明亮泛红天体，则是因其轮廓而得名的加州星云。由于加州星云要比昴宿星团暗淡很多，故较不易辨识。亦名为NGC 1499的泛红加州星云，离我们约1500光年远。虽然上面这二个天体相隔约25个满月的宽度，但这幅广角深空组合影像却能同时呈现两者。如仔细检视这幅深空影像，尚可找到恒星形成区IC 348及分子云LBN 777（小鹰星云）。
明日的图片: far star
