2025年9月29日
Two Camera Comets in One Sky
Image Credit & Copyright: Luc Perrot (TWAN)
Explanation: It may look like these comets are racing, but they are not. Comets C/2025 K1 ATLAS (left) and C/2025 R2 SWAN (right) appeared near each other by chance last week in the featured image taken from France’s Reunion Island in the southern Indian Ocean. Fainter Comet ATLAS is approaching our Sun and will reach its closest approach in early October when it is also expected to be its brightest — although still only likely visible with long exposures on a camera. The brighter comet, nicknamed SWAN25B, is now headed away from our Sun, although its closest approach to Earth is expected in mid-October, when optimistic estimates have it becoming bright enough to see with the unaided eye. Each comet has a greenish coma of expelled gas and an ion tail pointing away from the Sun.
Growing Gallery: Comet SWAN25B
Tomorrow’s picture: a third camera comet
双彗星同框于一片天空
影像提供与版权: Luc Perrot (TWAN)
说明: 这些彗星看起来像是在赛跑，但实际上并非如此。彗星C/2025 K1 ATLAS（左）和C/2025 R2 SWAN（右）上周偶然出现在一起，这张精选影像拍摄自在南印度洋法属留尼旺 岛。较暗的ATLAS彗星正接近太阳，并将在十月初达到最近距离，届时预计也将是其最明亮的时候——尽管仍然只有使用相机长时间曝光才能看到。昵称为SWAN25B的较亮彗星现在正远离太阳，但预计其最接近地球的时间在十月中旬，乐观估计届时它将变得足够亮，可用肉眼看到。每颗彗星都有一个由喷出的气体组成的绿色彗发，并有一条背向太阳的离子尾。
不断增长的画廊: 彗星SWAN25B
明日的图片: a third camera comet
