伦纳德彗星
Introducing Comet Leonard
Image Credit & Copyright: Dan Bartlett
Explanation: Here comes Comet Leonard. Comet C/2021 A1 (Leonard) was discovered as a faint smudge in January 2021 when it was out past Mars — but its orbit will take the giant shedding ice-ball into the inner Solar System, passing near both Earth and Venus in December before it swoops around the Sun in early January 2022. Although comets are notoriously hard to predict, some estimations have Comet Leonard brightening to become visible to the unaided eye in December. Comet Leonard was captured just over a week ago already sporting a green-tinged coma and an extended dust tail. The featured picture was composed from 62 images taken through a moderate-sized telescope — one set of exposures tracking the comet, while another set tracking the background stars. The exposures were taken from the dark skies above the Eastern Sierras (Mountains), near June Lake in California, USA. Soon after passing near the Earth in mid-December, the comet will shift from northern to southern skies.
APOD Editor (RJN) Online Monday: NASA’s Best Space Images (& Videos)
Tomorrow’s picture: moon building
伦纳德彗星
影像提供与版权: Dan Bartlett
说明: 李奥纳多彗星来了。在2021年1月发现伦纳德彗星（C/2021 A1 Leonard）之时，它只是火星轨道外头的一团暗淡光斑。不过这颗庞大蒸腾的冰球，将顺着它的轨道来到太阳系内围，在今年12月通过地球和金星附近，然后在2022年1月初旋绕过太阳。虽然彗星是以难以预测著称，不过仍有人预言伦纳德彗星会持续增亮，并在12月成为肉眼可见的彗星。在上面这幅摄于1个多星期前的影像里，李奥纳多彗星已然有泛绿的彗发，并曳着宽广的尘尾。这幅主题影像，是由1部中口径望远镜拍摄的62幅照片组合而成；其中部分照片是以彗星为导星，其它用于记录背景恒星。影像则摄于美国加州六月湖附近的东内华达山脉之幽暗天空下。在12月中旬通过地球附近之后，这颗彗星会从北天移入南天。
APOD编辑器(RJN)周一在线: NASA的最佳太空图像（和视频）
明日的图片: moon building
