但是当望远镜镜片直径翻一番时，如果设计不变，其重量会增加四倍。

But doubling the diameter of the telescope's mirror, without changing its design, would increase its weight fourfold.

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伽利略并没有发明望远镜，但在1609年听到有人制造了这种光学仪器后，他很快用管风琴管和眼镜镜片制造了自己的望远镜。

Galileo did not invent the telescope, but on hearing, in 1609, that such an optical instrument had been made, he quickly built his own device from an organ pipe and spectacle lenses.

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磨制巨型望远镜的镜片价格非常昂贵。

The lenses for giant telescopes are very expensive to grind.

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