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。

youdao

Yellowstone is at the northeastern end of the Snake River Plain, a great U-shaped arc through the mountains that extends from Boise, Idaho some 400 miles (640 km) to the west.

黄石公园是在蛇河平原的东北端。蛇河平原是一个巨大的U弧形，由爱达荷州的博伊西山脉向外延伸出来的群山向西大约400英里(640公里)。

youdao

As they pass through, they trace out an arc, just like a thrown ball falling due to gravity.

当中子穿越平板时，它们划出一道弧线，就像投出一个小球一样。

youdao

However, as the wicket livened up under the lights, Tendulkar came to the fore with a 102-ball masterclass featuring a sumptuous array of leg-side flicks and drives through the arc between point and cover.

BBC: Sachin Tendulkar is bowled off an inside edge

The YHT-697BL features HDMI 4K and 3D video pass-through with Audio Return Channel (ARC) and Yamaha's proprietary CINEMA DSP 3D audio to ensure that the system will deliver superior home theater experiences for years to come.

ENGADGET: Yamaha YHT-697 home theater in a box brings AirPlay, iPad connectivity to the masses

This negative is illuminated from the front by an arc lamp, and the light from this lamp passes through the transparent regions of the liquid-crystal layer to the middle layer.

ECONOMIST: Curtains for celluloid