北美洲星云位于天鹅座,靠近天津四(天鹅的尾部,也是天鹅座内最亮的一颗星)的一个发射星云。这个发射星云形似北美洲大陆,特别是东南的海岸,因而得名。(左)加利福尼亚星云是位于英仙座的一个发射星云,距离地球约1,000光年,由巴纳德于1884年发现。因在长时间曝光摄影下轮廓酷似美国加利福尼亚州的版图而得名。(右) The North American Nebula is located in Cygnus, a launching nebula close to Tianjin IV (the tail of the swan and also the brightest star in Cygnus). The launch nebula is named after the North American continent, especially the southeast coast. (Left) The California Nebula is a launch nebula in Perseus, about 1,000 light-years from Earth, discovered by Barnard in 1884. It is named for its contour resembling the outline of California in long exposure photography. (right)