球状星团M3前方的李奥纳德彗星

2021年12月12日

Comet Leonard Before Star Cluster M3
Image Credit & Copyright: Dan Bartlett

Explanation: Comet Leonard is now visible to the unaided eye — but just barely. Passing nearest to the Earth today, the comet is best seen this week soon after sunset, toward the west, low on the horizon. Currently best visible in the north, by late December the comet will best be seen from south of Earth’s equator. The featured image of Comet C/2021 A1 (Leonard) was taken a week ago from California, USA. The deep exposure shows in great detail the comet’s green gas coma and developing dust tail. The comet — across our inner Solar System and only light-minutes away — was captured passing nearly in front of globular star cluster M3. In contrast, M3 is about 35,000 light-years away. In a week, Comet Leonard will pass unusually close to Venus, but will continue on and be at its closest to the Sun in early January.

Tomorrow’s picture: meteor mountain

球状星团M3前方的李奥纳德彗星
影像提供与版权: Dan Bartlett

说明: 现在李奥纳德彗星是肉眼勉强可见的天体。在今天来到最近地球位置的这颗彗星，这星期会是最佳的时机，请在刚日落之后，往西方的地平线附近找。目前观赏这颗彗星的最好地点是在北半球，但是到12月底起，就会换成地球赤道以南。这幅以彗星C/2021 A1（李奥纳德）为主角的深空主题影像，是在2星期前摄于美国的加州，在其内可非常清楚见到彗星泛绿的彗发和愈来愈长的尘尾。拍摄这幅影像时，这颗离我们只有数光分远的彗星，在通过太阳系内围的旅程中，几乎位在球状星团M3之前方；相较之下，M3约为35,000光年远。在这星期，李奥纳德彗星会极近距通过金星附近，然后在明年的1月底，行进到最接近太阳的位置。

明日的图片: meteor mountain