apparent diameter

简明释义

视直径

英英释义

例句

1.When observing the moon, its apparent diameter appears larger when it is closer to the horizon.

观察月球时，当它靠近地平线时，其视直径看起来更大。

2.In photography, understanding the apparent diameter of lenses can affect the depth of field in images.

在摄影中，理解镜头的视直径可以影响图像的景深。

3.The apparent diameter of the sun is about 0.5 degrees as seen from Earth.

从地球上看，太阳的视直径约为0.5度。

4.The telescope can measure the apparent diameter of celestial bodies, which helps astronomers determine their size and distance.

望远镜可以测量天体的视直径，这帮助天文学家确定它们的大小和距离。

5.The apparent diameter of a star can change due to atmospheric conditions.

由于大气条件的变化，一颗恒星的视直径可能会改变。

作文

In the field of astronomy, understanding celestial objects is crucial for both amateur and professional astronomers. One of the key concepts that often arises in discussions about stars, planets, and other astronomical bodies is their size as perceived from Earth. This perception is quantified by a term known as apparent diameter, which refers to the visual size of an object as seen from a particular vantage point. While the actual size of an object may be vast, its apparent diameter can vary significantly depending on the observer's distance from it and the object's intrinsic brightness. For instance, when we look at the Moon, its apparent diameter appears much larger than that of distant stars, even though those stars are immensely larger in size. The reason behind this phenomenon lies in the vast distances separating us from these celestial bodies. The Moon is relatively close to Earth, about 384,400 kilometers away, which allows us to see it as a sizable object in our sky. In contrast, stars are light-years away, making their apparent diameter appear minuscule despite their actual physical dimensions. The concept of apparent diameter is not only relevant in astronomy but also extends to various fields such as optics and photography. In optics, the apparent diameter of lenses determines how much light they can gather and how clearly they can focus images. A lens with a larger apparent diameter can collect more light, resulting in brighter images and better performance in low-light conditions. Similarly, photographers often consider the apparent diameter of their camera lenses when selecting equipment for different shooting scenarios. Moreover, apparent diameter plays a significant role in the study of exoplanets. When astronomers observe a star and notice a dip in its brightness, they may conclude that a planet is transiting in front of it. The size of the planet, as inferred from the light curve, can be understood in terms of its apparent diameter. The smaller the dip in brightness, the smaller the planet's apparent diameter in relation to the star. This relationship allows scientists to estimate the sizes of these distant worlds, contributing to our understanding of planetary systems beyond our own. In conclusion, the term apparent diameter encapsulates a fundamental aspect of how we perceive celestial and optical objects. It highlights the difference between an object's true size and how it appears to an observer. By grasping the significance of apparent diameter, we can better appreciate the complexities of our universe and the tools we use to explore it. Whether it's through the lens of a telescope or the aperture of a camera, the apparent diameter remains a critical concept that bridges the gap between reality and perception.

在天文学领域，理解天体对于业余和专业天文学家来说都是至关重要的。在关于星星、行星和其他天体的讨论中，常常会出现一个关键概念，即它们从地球上看起来的大小。这个感知通过一个术语来量化，称为表观直径，它指的是从特定视角看到的物体的视觉大小。虽然一个物体的实际大小可能是巨大的，但其表观直径可能会因观察者与物体之间的距离和物体的内在亮度而显著变化。例如，当我们观察月球时，它的表观直径看起来比遥远的星星大得多，尽管那些星星的实际尺寸巨大。这种现象背后的原因在于将我们与这些天体分开的巨大距离。月球离地球相对较近，约384,400公里，这使我们能够将其视为天空中的一个较大物体。相比之下，星星距离我们数光年，使得它们的表观直径显得微不足道，尽管它们的物理尺寸实际上很大。表观直径的概念不仅在天文学中相关，还扩展到光学和摄影等多个领域。在光学中，镜头的表观直径决定了它们能收集多少光以及如何清晰地聚焦图像。具有较大表观直径的镜头可以收集更多光，从而在低光条件下产生更明亮的图像和更好的性能。同样，摄影师在选择不同拍摄场景的设备时，常常考虑他们相机镜头的表观直径。此外，表观直径在外行星研究中也发挥着重要作用。当天文学家观察一颗恒星并注意到其亮度下降时，他们可能会得出结论，认为有一颗行星正在其前面经过。通过光曲线推断出的行星大小，可以用其表观直径来理解。亮度下降越小，行星的表观直径相对于恒星就越小。这一关系使科学家能够估计这些遥远世界的大小，从而有助于我们理解超出自身的行星系统。总之，术语表观直径概括了我们感知天体和光学物体的基本方面。它突出了物体真实大小与观察者眼中所呈现之间的差异。通过掌握表观直径的重要性，我们可以更好地欣赏我们宇宙的复杂性以及我们用来探索它的工具。无论是通过望远镜的镜头还是相机的光圈，表观直径仍然是一个关键概念，架起了现实与感知之间的桥梁。