作者flyingwave (飞翔的波)
看板sky
标题[问题] 天文杂志中句子的疑问
时间Tue Mar 31 22:07:44 2009
The second scale is given in the well-known
astronomical scale of magnitude
per arc second (mag/sec2) in the visual range (V-band). This gives the
brightness of the sky of one square arc second. The natural level is around
21.6 mag/sec2 at a solar activity minimum.
不懂红色字的地方 请高手解惑~thx
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