The city light patterns are very clear, indicating that there was little cloud cover or haze in the region at the time.

而城市的光圈非常清晰，表示当时这块区域上空较少阴霾和云层。

youdao

And when I shall put thee out, I will cover the heaven, and make the stars thereof dark; I will cover the sun with a cloud, and the moon shall not give her light.

我将你扑灭的时候，要把天遮蔽，使众星昏暗，以密云遮掩太阳，月亮也不放光。

youdao

The reason the cloud cover seems broken, revealing light, only at the edges of the circle is due to the rapid movement of swirling air at the edges.

云层看起来破碎，而且只在圆圈的边上投出光线的原因就是因为边上的旋转空气在快速移动。

youdao

Despite his hopes for Saturday's first session, Finn said it was "obviously frustrating" that England were not able to take the new ball with thick cloud cover overhead on Friday evening as the umpires ruled the light had become too poor.

BBC: Ashes: Early start suits England, says Steven Finn