2020 June 6
Explanation: Comet PanSTARRs, C/2017 T2, shared this stunning telescopic field of view with galaxies M81 and M82 on May 22/23. Of course, the galaxies were some 12 million light-years distant and the comet about 14 light-minutes away, seen in planet Earth’s sky toward the Big Dipper. A new visitor from the Oort Cloud, this Comet PanSTARRs was discovered in 2017 by the PanSTARRs survey telescope when the comet was over 1 light-hour from the Sun, almost as distant as the orbit of Saturn. With a beautiful coma and dust tail, this comet has been a solid northern hemisphere performer for telescope wielding comet watchers this May, following its closest approach to the Sun on May 4. In this deep image from dark California skies the outbound comet even seems to develop a short anti-tail as it leaves the inner Solar System.
Tomorrow’s picture: planetary nebula
说明: 在这幅令人惊艳摄于5月22/23日晚的精采望远镜影像里，泛星彗星（C/2017 T2）和星系M81与M82共享这片视野。不过从地球往北斗七星的方向看出去，这对星系的距离约有1千2百万光年远，而彗星则近在14光分远之处。 泛星彗星这个来自欧特云的新访客，是在2017年发现于泛星的巡天望远镜影像中；在当时，这颗彗星离太阳约1光时，约莫是土星轨道的2倍远。在今年5月4日通过近日点之后，对使用望远镜的观星者来说，这颗曳着美丽彗发和尘埃尾的彗星，算是相当精采的天体。在这幅摄于加州幽暗星空下的深空影像里，这颗远离的彗星在告别太阳系内围时，甚至发展出短短的反彗尾。
明日的图片: planetary nebula