字谜

Definition: “Adjective identifying the second surface to reflect radiation in a telescope. In a radio telescope, the primary reflector is usually the surface of the panels or, in a low-frequency antenna, a wire mesh. This is sometimes referred to as the main reflector or simply, the dish. The _________ reflector, if any, is often called the subreflector.”

第一个字母: S

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这个单词是什么?

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