Thanks to all! Here is how it was taken:

来源: pieq314 于 2011-11-24 20:33:22 [] [博客] [旧帖] [给我悄悄话] 阅读数 : 0 (416 bytes)
本帖于 2011-11-26 17:24:07 时间, 由普通用户 akuan 编辑
回答: Horsehead Nebula 由 pieq314 于 2011-11-24 13:58:17

The telescope is a 90cm astronomical telescope.  The camera is black & white.  When taking this color photo, 4 filters were used: red, green, blue and IR block.  10 photos were taken with each filter, and the 10 photos are combined into one for better signal to noise ratio.  At the end, the resulting 4 photos (corresponding to the 4 filters) were combined into a single color filter.

所有跟帖： 

• 厉害！黑乎乎的东东是啥？ -梦中画- ♀ 给 梦中画 发送悄悄话 梦中画 的博客首页 (0 bytes) () 11/25/2011 postreply 18:15:27

• That is a dark cloud/dust in space. -pieq314- ♀ 给 pieq314 发送悄悄话 pieq314 的博客首页 (85 bytes) () 11/26/2011 postreply 20:08:13

• "10 photos are combined" 很酷，看来这是减轻噪点的常用方法 -akuan- ♂ 给 akuan 发送悄悄话 (33 bytes) () 11/26/2011 postreply 05:45:40

• Yeah, it is the last weapon for dealing with dim subjects. -pieq314- ♀ 给 pieq314 发送悄悄话 pieq314 的博客首页 (93 bytes) () 11/26/2011 postreply 20:18:52

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