And mathematically, you can express that in terms of how much that object subtends.

从数学 上讲，您可用该对象对向程来表达这一点。

An object is said to subtend a certain angle of your vision based on how close you are to it, and how big it is.

根据您 与它接近程它大小，据说一个物体对着您视野某个。

So if you look at our tiny leaf, it may subtend only two degrees of your vision when it’s at your near point – say, 25 centimeters away.

所如果看着我们小叶子，当它近点——比如 25 厘米远——时，它可能只对着两视线。

But when you look at the leaf through the lens, the virtual image is larger than the actual object, so it subtends six degrees of your vision.

但是当通过镜头看树叶时 ，虚像比实际物体大， 所它对着视线六。

So if you look at our tiny leaf, it may subtend only two degrees of your vision when it's at your near point – say, 25 centimeters away. .

因此，如果您看我们小叶子， 当它您近点（例如 25 厘米远）时，它可能只对着您视线两。

In order to find the magnifying power of the lens, you just divide the angle subtended by the virtual image by the angle subtended by your unaided eye.

为了求出镜片放大倍率 ，只需用虚 像对除肉眼对。

And the newly subtended angle is the amount that the object subtends when viewed through the eyepiece – the angle between your eye and the rays from the eyepiece.

新对向是通过目镜观察物体时对向量——眼睛与目镜发出光线之间。

For example, if you’re looking up at the moon, and you cover it with your thumb, then your thumb and the moon are both subtending the same angle to your eye, which we measure in degrees.

例如，如果您正抬头看月亮，并用拇指遮住它，那么您拇指和月亮都会与您眼睛形成相同，我们为单位进行测量。

For example, if you're looking up at the moon, and you cover it with your thumb, then your thumb and the moon are both subtending the same angle to your eye, which we measure in degrees.

例如，如果抬头看着月亮，然后用拇指遮住它，那么拇指和月亮都对着眼睛，我们用数来衡量这个。