We also studied simple magnifiers and how to generate an enlarged virtual image.

我们还研究了简单的放大镜以及 如何生成放大的虚拟图像。

By 1877 telescopes could enlarge the image of the distant planet, so that it appeared roughly the size of a dime held at arm's length.

在1877年，望远镜能够放大远方行星的映象，所以它看起来大致如同放在胳膊长度的一角硬币。