2025年5月21日
International Space Station Crosses the Sun
Image Credit & Copyright: Pau Montplet Sanz
Explanation: Typically, the International Space Station is visible only at night. Slowly drifting across the night sky as it orbits the Earth, the International Space Station (ISS) can be seen as a bright spot about once a month from many locations. The ISS is then visible only just after sunset or just before sunrise because it shines by reflected sunlight — once the ISS enters the Earth’s shadow, it will drop out of sight. The only occasion when the ISS is visible during the day is when it passes right in front of the Sun. Then, it passes so quickly that only cameras taking short exposures can visually freeze the ISS’s silhouette onto the background Sun. The featured picture did exactly that — it is actually a series of images taken a month ago from Sant Feliu de Buixalleu, Spain with perfect timing. This image series was later combined with a separate image highlighting the texture of the active Sun which included several Sun’s prominences around the edge.
Celestial Surprise: What picture did APOD feature on your birthday? (post 1995)
Tomorrow’s picture: curly spiral galaxy
凌越太阳的国际空间站
影像提供与版权: Pau Montplet Sanz
说明: 通常只有在夜间才能看见国际空间站。在夜晚时，绕行地球的国际空间站 (ISS) 会缓慢的飘过夜空，从许多地方看出去，大约每个月有一次机会见到以亮斑之姿现身的国际空间站。不过，国际空间站只有在即将日落或日出时才得见，因为国际空间站的光是来自所反射的阳光，一旦国际空间站进入地球的影子里，它就消失匿迹。要在白天见到国际空间站，唯一可能的情况是它通过太阳的正前方。在此情况下，国际空间站会快速掠过日盘，只有进行短曝光的相机，才能在视觉上把国际空间站的剪影定格在后方的日盘上。这幅主题影像，正是这种曝光时间恰到好处的体现。这幅影像整合了摄于西班牙圣费利乌－德布克萨列乌村（Sant Feliu de Buixalleu）的系列快照，然后再与一张突显活跃太阳纹理及临边日珥的底图叠合而成。
天赐惊喜: 你生日那天APOD刊登了什么照片？（1995年后）
明日的图片: curly spiral galaxy
