泰坦影凌日
(原标题: Titan Shadow Transit)
2025-07-24
浏览次数: 1500
每隔15年左右，土星的光环就会向我们的视线倾斜。随着明亮、美丽的光环系统变得越来越窄、越来越暗淡，地球上的居民越来越难以看到它。但它确实提供了观察土星卫星凌日的机会，以及它们在这个环状气体巨星仍然明亮的圆盘上的阴影。当然，土星最大的卫星土卫六是最容易被发现的。在这张7月18日的望远镜快照中，土卫六本身位于左上方，在土星窄窄的光环上方的带状云顶上投下了一个圆形的黑影。事实上，土卫六的凌日季节现在正如火如荼地进行着，每16天就有一次影子凌日，与土卫六的轨道周期相对应。它的最后一次影子凌日将在10月6日，尽管从地球上的望远镜每16天看到一次，土卫六的苍白圆盘将继续穿过土星前面，直到2026年1月25日。
查看原文解释
very 15 years or so, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful ring system grows narrower and fainter it becomes increasingly difficult to see for denizens of planet Earth. But it does provide the opportunity to watch transits of Saturn's moons and their dark shadows across the ringed gas giant's still bright disk. Of course Saturn's largest moon Titan is the easiest to spot in transit. In this telescopic snapshot from July 18, Titan itself is at the upper left, casting a round dark shadow on Saturn's banded cloudtops above the narrow rings. In fact Titan's transit season is in full swing now with shadow transits every 16 days corresponding to the moon's orbital period. Its final shadow transit will be on October 6, though Titan's pale disk will continue to cross in front of Saturn as seen from telescopes on planet Earth every 16 days through January 25, 2026.
© Every 15 years or so