2019 September 20

Saturn at Night
Image Credit:
NASA, JPL-Caltech, Space Science Institute, Mindaugas Macijauskas

Explanation: Still bright in planet Earth’s night skies, good telescopic views of Saturn and its beautiful rings often make it a star at star parties. But this stunning view of Saturn’s rings and night side just isn’t possible from telescopes closer to the Sun than the outer planet. They can only bring Saturn’s day into view. In fact, this image of Saturn’s slender sunlit crescent with night’s shadow cast across its broad and complex ring system was captured by the Cassini spacecraft. A robot spacecraft from planet Earth, Cassini called Saturn orbit home for 13 years before it was directed to dive into the atmosphere of the gas giant on September 15, 2017. This magnificent mosaic is composed of frames recorded by Cassini’s wide-angle camera only two days before its grand final plunge. Saturn’s night will not be seen again until another spaceship from Earth calls.

NASA, JPL-Caltech, Space Science Institute, Mindaugas Macijauskas

说明: 目前在地球夜空中仍然很明亮的土星,望远镜可清楚见到它的身影和美丽的环系,因此成为观星派对的明星。然而,这幅精采影像所呈现的环系和土星夜面,是比外行星更靠太阳的望远镜见不到景观;这些望远镜只能为我们带来土星的白昼面。其实,这幅记录土星美丽蛾眉日耀区和投射在庞大复杂环系上的暗影之影像,是来自卡西尼号太空船。来自地球的卡西尼号无人太空船,长达13年以土星轨道为家,然后在2017年9月15日接获指令,跃入这颗气态巨行星的大气。这幅壮丽的拼接影像,组合自卡西尼号最后舍身一跃的前二天,其广角相机拍摄的多幅照片。土星的夜面景观将不再复现,除非未来有其他地球的太空船再次造访。