The amount of sky that you can view through a telescope is called the real (true) field of view and is measured in degrees of arc (angular field).

通过望远镜你所能看到的天空的范围称作真实视场，以弧度值(角视场)来度量。

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The main advantage of fast focal ratios with a telescope used visually is a wider field of view.

快焦比的主要优点在于可以提供一个更宽的视角。

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For example, a telescope with a focal length of 2000mm has twice the power and half the field of view of a 1000mm telescope.

比如，与焦距为1000mm的望远镜相比，2000mm焦距望远镜的放大率和视场范围分别是前者的2倍和1/2。

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The Pan-Starrs telescope in Hawaii uses several gigapixel cameras, but it has a relatively narrow field of view.

WSJ: Next Cameras Come Into View