氢-α

A starfield is shown filled with red glowing gas. On the right is a blue-glowing complex nebula, while on the left there is a long encircling arc of red gas. Please see the explanation for more detailed information.
图中展现了一片充满红色发光气体的星空。右侧是一片发出蓝色光芒的复杂星云，左侧则是一圈环绕的红色气体弧。有关更多详细信息，请参阅说明。