China Space Station streaks across the sky at 4:47 a.m. Beijing times, atop of the silhouette of the ancient Bell Tower of Beijing, Beijing, China, May 2, 2021. /CFP
对于全国，乃至全世界的天文爱好者来说，这个夏天多了一个“休闲娱乐”的好消遣——观测中国空间站。近日来，中国空间站“天和”核心舱的频繁过境引起了各地天文爱好者关注。
“天和”核心舱于今年4月29日成功发射，随后，神舟十二号航天员乘组于6月17日进驻核心舱。核心舱整体约相当于一套三居室公寓的大小，在合适的地点和光线条件下，地面上的人用肉眼就可以观察到。
Here's good news for stargazing enthusiasts: there's an interesting new target to gaze at on a sultry summer nights this year – China Space Station.It's already become a new summer hobby for many. After the sun sets, they look above for signs of the China Space Station, a spacecraft carrying three men. Sometimes its huge body and pair of solar wings – combined, roughly the size of a three-bedroom apartment – is bright enough for Earthlings to see with naked eyes. It looks like a tiny, bright moving dot streaking across the night sky.这颗距地球三百多公里的“人造”星星大约每90分钟绕地球一周，这意味着它每天要经历 16 次日出和日落，几乎每一个半小时都可能从我们头顶路过。但是，要实现肉眼观测核心舱并没有那么容易。白天，地面上的光线太亮而核心舱亮度不够，不利于观察；而晚上，当核心舱运行至地球的阴影中时，我们也无法看到。最佳“追星”时间是傍晚或凌晨——当太阳形成一个可被舱体反射光线的角度时。
The space station, 380 kilometers above the Earth, has been orbiting the blue planet about once every 1.5 hours since earlier this year meaning it travels through 16 sunrises and sunsets every day.In the daytime, it's too bright on the ground to see but it's also invisible at late night when it orbits into the shadow of the Earth. The best time to check it out is around dawn or dusk, when the sky is dim and the sun is at an angle, so its rays catch the ship as it flies over."You need to know where and when it will appear," Kou Wen, an expert at the Beijing Planetarium, told a local newspaper.为了方便天文爱好者们随时掌握“追星”动态，许多专业的网站、软件和小程序都提供了供感兴趣的公众查看“天和”核心舱过境的时间、方位角和亮度等信息的服务。
据专家介绍，从太阳角度、大气通透度、空间站高度角、过境轨道、观测者所处地理位置等综合因素来考虑，7、8月份应该是最佳观测期。
Screenshot via TianwentongMany professional astronomical websites and apps provide information for astronomers to track stars and satellites such as non-profit website Heavens-Above and a mini-program on WeChat called Astro-Meteo Tools, or Tianwentong. Through these platforms, once you set up your current location, you can get a list of visible passes on different dates, and voila! You can start your stargazing.Kou said it will visible to anyone who looks up as long as it's a clear day and seen from a location that isn't very well lit at ground level. "If you can see stars, then you are in the right location to spot the space station."The space station "looks like a bright star, slowly streaking across the sky, almost like a plane passing by without the lights blinking", according to the Beijing Academy of Science and Technology.与此同时，一群“高阶”天文发烧友正期待着见证空间站“凌日”——即空间站恰巧从太阳和地球之间经过，对太阳有所遮挡的天文现象。不过，这就需要更专业的观测设备和更精准的观测预报了。Advanced astronomers are looking forward to what is known as "the astronomical transit", a phenomenon that occurs a celestial body passes directly between a larger object and the observer. In this case, when the space station passes between the Earth and the sun or the moon. This kind of observation will require professional equipment – especially when passing in front of the sun – and a more accurate predictor.