Neptune was the first planet to be discovered through mathematical predictions instead of being seen, as it is too faint to be observed with the unaided eye.

它还是数学测算而非观测发现的行星，于它太过暗淡，所以无法用肉眼观察到。

I don't know where you dipshits got this one from. First of all, there's no way you could see it with the unaided eye.

我不知道你是从哪里听来的，先，你不可能用肉眼看到它。

Interesting tidbit: It actually is visible to the unaided eye if you have very sharp eyesight and very dark skies.

如果你的视力很好，而且天空很暗，你可以直接用肉眼看到它。

A parade of four or five planets visible to the unaided eye happens every few years.

每隔几年会有四五颗肉眼可见的行星出现。

Galileo was the first to discover, or at least record, the fact that they were actually composed of many stars so close together our unaided eyes couldn't resolve them.

伽利略是第一发现，或者至少记录了这样一事实：它们实际上是许多靠得很近的恒星组成的，我们的肉眼无法分辨它们。

Although it is possible to see Uranus with the unaided eye in good viewing conditions, it was never recognized by ancient peoples as a planet because it was so dim and moved so slowly.

尽管可能在一好天气里可以看肉眼看到天王星，但是因为过暗和绕行缓慢，古代监测者并没有发现它是行星。

Although two of the planets are not visible to the unaided eye, all are on the same side of the sun during the evening hours.

尽管中两颗行星肉眼不可见，但在晚上它们都在太阳的同一侧。

Four were visible to the unaided eye.

中四颗肉眼可见。

Clearly, there were far more stars in the sky than the 6000 or so visible to our unaided eyes.

显然，天空中的星星要比我们肉眼可见的6000颗星星还要多得多。

Given the differences in the spectrums of light they each are able to detect, the JWST  can't ever provide what Hubble can – a clear picture of what these planets actually would  look like to the unaided human eye.

考虑到它们各自能够探测到的光谱的差异，JWST 无法提供哈勃望远镜所能提供的——这些行星在肉眼看来实际上是什么样子的清晰图像。

The original subtended angle is the subtended angle of the unaided eye – the angle between the center of the objective lens and the height of the real image.

原始张角是未使用辅助工具的眼睛的张角——即物镜中心与实像高之间的角。

It will go from requiring a small telescope to see all the way up to becoming visible to the unaided eye about as bright as the North Star Polaris.

它将从需要小型望远镜才能看到，一直到肉眼可见，可比北极星。

But for the unaided eye, the first exploding star visible since Kepler, in the 1600s was in 1987.

然而，对于裸眼观测者来说，自17世纪开普勒时代以来，第一颗可见的爆炸恒星出现在1987年。

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.

为了求出镜片的放大倍率 ，只需用虚 像对角除以肉眼对角。