2024年最美的彗星已经在天空中可见了！目前，南半球的观测者正在欣赏明亮的C/2023 A3（紫金山-阿特拉斯）彗星，很快北半球也能看到它了。

The best comet of 2024 is already visible in the sky! Right now, observers in the Southern Hemisphere are enjoying the brightening Comet C/2023 A3 (Tsuchinshan-ATLAS), and soon it will be visible in the Northern Hemisphere as well.

首先，彗星C/2023 A3（紫金山-阿特拉斯）可能非常明亮，同时预计也会有漂亮的尾巴，C/2023 A3在水星轨道内经过太阳后，其尘埃和冰彗发将变得非常热。冰会蒸发并逸入太空，并带走大量尘埃颗粒，这些尘埃颗粒会延伸成一条长而明亮的尾巴。历史表明，靠近太阳的彗星拥有最令人印象深刻的彗尾，彗星C/2023 A3正是如此！

First of all, C/2023 A3 (Tsuchinshan-ATLAS) is likely to be very bright, and a beautiful tail is also expected.After passing by the Sun at a distance similar to Mercury's orbit, C/2023 A3's coma of dust and ice will heat up considerably. As the ice particles evaporate, they will quickly escape into space, taking with them a large amount of dust that will extend into a long, bright tail. As history shows, comets that pass close to the Sun have the most impressive tails, formed soon after being "roasted" by the Sun's heat. And this is the case with comet C/2023 A3!

图片展示了2007年的麦克诺彗星，展示着它美丽的大尾巴。This image shows Comet McNaught in 2007, showing its beautiful tail.（©ESO/Sebastian Deiries）

C/2023 A3 (紫金山-阿特拉斯) 彗星现在已在南半球可见！您可以在早晨日出前看到彗星，它位于东方天空的低处。为了获得最佳视野，请使用放大倍数更高的双筒望远镜，例如10x50或12x50，这对于位于地平线上方低处的彗星来说是更好的选择。

Comet C/2023 A3 (Tsuchinshan-ATLAS) is now visible in the Southern Hemisphere! You can see the comet in the morning, low in the eastern sky, just before sunrise. To get the best view, use binoculars with higher magnification, such as 10x50 or 12x50, which are preferable for comets low on the horizon.

这颗彗星的亮度为约4.7等，比预期的要亮，而且每天都在变亮。请记住，当彗星在黑暗的天空中达到约4等时，肉眼就能看到。

The comet has a magnitude of about 4.7, which is brighter than expected, and it is getting brighter each day. Remember, comets can be seen with the naked eye when they reach a magnitude of about 4 in a dark sky.

尽管这颗彗星距离太阳很近（距角≤23°），但许多观测者即使在困难的条件下也能看到这颗彗星。

Even though the comet is close to the Sun (with an elongation of ≤23°), many observers manage to see the comet even under difficult conditions. Every day, new images of C/2023 A3 appear on the Internet.

在北半球，彗星更靠近地平线，由于太阳太亮，很难看到。它将于10月初在北纬地区可见。

In the Northern Hemisphere, the comet is closer to the horizon and hard to see because of the Sun’s brightness. It will become visible in northern latitudes in early October.

C/2023 A3（紫金山-阿特拉斯）彗星在2024年能见度预测

C/2023 A3 (Tsuchinshan-ATLAS) visibility forecast for 2024

以下是未来几周C/2023 A3 (紫金山-阿特拉斯) 彗星可见度的预测：

Here are the predictions for the visibility of C/2023 A3 (Tsuchinshan-ATLAS) in the coming weeks:

9月18日至26日：亮度从4.7到3.0等，出现在南半球早晨的天空中，位于东方地平线上的低处，在六分仪座中。需要双筒望远镜（最好是10x50或12x50）。这是观察彗星尾（可能是双尾）的好时机。September 18-26: from 4.7 to 3.0 mag, appears in the morning sky in the Southern Hemisphere, low above the eastern horizon in the constellation of Sextans. Requires binoculars (preferably 10x50 or 12x50). Good time to observe the cometary tail (possibly double tail).
9月27日至10月2日：亮度从3.0到0.0等，于9月27日到达距离太阳最近的点（近日点），出现在南半球和北半球（北纬40°以下）的早晨天空中。9月28日从六分仪座进入狮子座。肉眼可能可以看到。September 27-October 2: from 3.0 to 0.0 mag, reaches the closest point to the Sun (perihelion) on September 27, appearing in the morning sky in the Southern Hemisphere and in the Northern Hemisphere (below 40°N). Passes from the constellation of Sextans into the constellation of Leo on September 28. May be visible to the naked eye.
10月2日至9日：亮度从0.0到-3.0等，但距离太阳太近，肉眼无法看到。在采取必要预防措施的情况下，可以在早晨用望远镜观察和拍摄。最乐观的预测认为彗星的亮度将超过-5.0等；如果是这样，即使在白天肉眼也可以看到它。October 2-9: from 0.0 to -3.0 mag, but too close to the Sun to be visible to the naked eye. Can be observed and photographed with a telescope in the morning with the necessary precautions. The most optimistic forecasts say that the comet will exceed magnitude -5.0 — if so, it'll be visible to the naked eye even in the daytime sky close to the Sun.
10月10日至12日：亮度从-3.0到-1.0等，在北半球日落后不久的傍晚出现，位于西边天空非常低的位置，在处女座中。观察窗口很短，但彗星可以用肉眼看到！观看彗星的最佳时间。10月12日最接近地球。October 10-12: from -3.0 to -1.0 mag, appears in the evening in the Northern Hemisphere shortly after sunset, very low in the western sky in the constellation of Virgo. Short observation window, but visible with the naked eye! Best time to see the comet. Makes its closest approach to Earth on October 12.
10月13日至14日：亮度从-1.0到1.0等，迅速减弱，但距离太阳较远，因此更容易被看到。日落后约一小时，傍晚肉眼可见。10月14日，C/2023 A3彗星将靠近另一颗彗星13P/奥伯斯（10等）。October 13-14: from -1.0 to 1.0 mag, quickly losing brightness, but moving farther from the Sun and therefore easier to see. Visible with the naked eye in the evening about an hour after sunset. On October 14, C/2023 A3 will pass close to another comet, 13P/Olbers (mag 10).
10月15日至19日：亮度从1.0到4.5等，朝巨蛇座的头部移动。可能产生反尾，即一条明亮的条纹，似乎指向太阳，与其他彗星尾巴相对。10月15日，彗星将经过距离M5球状星团1.4°处，提供良好的拍照机会。October 15-19: 1.0 to 4.5 mag, moving toward Serpens Caput. May produce an anti-tail — a bright streak that appears to be pointing toward the Sun, opposite the other tails. On October 15, it will pass 1.4° from the M5 globular cluster, providing a good photo opportunity.
10月20日至31日：亮度从4.5到7.0等，穿过蛇夫座，位于西南天空相对较高的位置，晚上可见。用双筒望远镜和望远镜可见。在这几天里，彗尾将开始快速增长，可能达到20°长（约为满月大小的40倍）。October 20-31: 4.5 to 7.0 mag, moving across the constellation Ophiuchus relatively high in the southwestern sky in the evening. Visible with binoculars and telescopes. During these days, the tail of the comet will begin to grow rapidly, possibly reaching up to 20° long (about 40 times the size of the Full Moon) under dark skies.
11月：亮度从7到8等，晚上可见。日落后在北半球升得更高。November: from 7 to 8 mag, visible in the evening. Rises higher in the Northern Hemisphere after sunset.
12月：亮度从8到10等，在天空中逐渐靠近太阳，升到地平线以下。在南半球不可见。December: from 8 to 10 mag, gradually moves closer to the Sun in our sky, rising lower above the horizon. Not visible from the Southern Hemisphere.

请记住，彗星的亮度在星等为4左右时才可以用肉眼看到。星等测量的是物体上分布的总光量，因此，对于恒星或行星等精确光源，肉眼可见度极限较低（星等6.5），而对于彗星或星系等弥散物体，肉眼可见度极限较高。

Remember that comets become visible to the naked eye at around magnitude 4. The magnitude scale measures the total light spread over the object, so the naked-eye visibility limit is lower (mag 6.5) for pinpoint sources of light, like stars or planets, and higher for diffuse objects, like comets or galaxies.

C/2023 A3彗星穿过太阳系的路径（2024年）

C/2023 A3 (Tsuchinshan-ATLAS) approaching the Earth in 2024: path through the Solar System

9月：C/2023 A3彗星将进入金星轨道。9月27日，这颗彗星将经过近日点，这意味着它将距离太阳最近，距离为0.39天文单位。在此期间，该彗星可能会在高温的冲击下分裂。September: comet C/2023 A3 will enter Venus’s orbit. On September 27, the comet will pass perihelion, meaning it will come the closest to the Sun, at a distance of 0.39 AU. During this period, the comet may break apart under the impact of the high temperature.
10月：如果C/2023 A3彗星在近日点幸存下来，那么在10月12日，它将距离地球最近，与地球的距离为0.48个天文单位。它将达到最大亮度并且即使用肉眼也可以观察到。October: if C/2023 A3 survives perihelion, then on October 12, it will come the closest to the Earth and will be at a distance of 0.48 AU from our planet. It will reach maximum brightness and be observable even with the naked eye.
11月：C/2023 A3彗星将随着远离地球而逐渐失去亮度。到11月底，彗星与地球之间的距离将增加到1.94个天文单位。在接下来的20年中，这颗彗星将移向太阳系边缘，并且在接下来的26,000年内不会返回。November: C/2023 A3 will gradually lose its brightness as it will move away from the Earth. By the end of the month, the distance between the comet and our planet will increase to 1.94 AU. For the next 20 years the comet will be moving toward the edge of the Solar System and will not return for another 26,000 years.

观测C/2023 A3（紫金山-阿特拉斯）的最佳时间：它会变得多亮？

Best time to observe C/2023 A3 (Tsuchinshan-ATLAS): how bright will it get?

彗星C/2023 A3（紫金山-阿特拉斯）将在10月12日左右达到峰值亮度，届时它将以距离地球最近的距离（0.48天文单位）经过。很难预测彗星的确切亮度；大多数天文学家倾向于认为它的亮度足以用肉眼看到。

Comet C/2023 A3 (Tsuchinshan-ATLAS) will reach its peak brightness around October 12, when it will pass at its closest distance to the Earth (0.48 AU). It's hard to predict the exact brightness of the comet — most tend to think it will be bright enough to be visible to the naked eye.

10月9日至12日，由于前向散射的影响，C/2023 A3可能会增亮至-4.0等！相比之下，20世纪最著名的彗星之一海尔-波普彗星的峰值星等为-1.8。所谓的绿色彗星C/2022 E3（ZTF）在2023年初趋于活跃，其最大星等达到5.4等。著名彗星NEOWISE（C/2020 F3）的亮度为0.9等。

On October 9-12, due to the effect of forward scattering, C/2023 A3 might brighten up to -4.0 magnitude! By comparison, the comet Hale-Bopp, one of the most widely observed comets of the 20th century, had a peak magnitude of -1.8. The so-called green comet C/2022 E3 (ZTF), which was trending at the beginning of 2023, reached a maximum magnitude of 5.4. The famous NEOWISE (C/2020 F3) peaked at 0.9.

您最早可以在九月底开始在早晨的天空中寻找彗星。黎明前，它会在很低的天空中可见。 *9月27日彗星C/2023 A3（紫金山-阿特拉斯）将尽可能接近太阳（0.39天文单位）。最好的情况下，此时彗星将达到-1等；最坏的情况是亮度为4等，在非常黑暗的天空中肉眼几乎看不见。

To extend the show, start looking for the comet in the morning sky at the end of September. It will be visible very low in the sky before sunrise. On September 27, C/2023 A3 (Tsuchinshan-ATLAS) will make its closest approach to the Sun (0.39 AU). At best, C/2023 A3 will have a magnitude of -1 at this time; at worst, it will have a magnitude of 4 (barely visible to the naked eye under very dark skies).

经过近日点后，C/2023 A3（紫金山-阿特拉斯）将消失一段时间，并将于2024年10月上旬重新出现在夜空中。直到本月底，它仍将是晚间活动。然而，10月12日之后，这颗彗星将开始迅速消退，到月底将不再用肉眼看到。

After the perihelion, C/2023 A3 (Tsuchinshan-ATLAS) will disappear for a while and reappear in the evening sky in early October 2024. It will remain an evening object until the end of the month. However, after October 12, the comet will fade out rapidly and won’t be visible to the naked eye by the end of the month.

如何拍摄C/2023 A3（紫金山-阿特拉斯）彗星？

How to photograph Comet C/2023 A3 (Tsuchinshan-ATLAS)?

最好在10月11日至15日晚上拍摄C/2023 A3彗星。要拍摄彗星，您需要：

Aim to photograph C/2023 A3 between October 11 and 15 in the evening as soon as you spot the comet. To photograph the comet, you'll need:

Seestar S50或其他相机（Seestar S50 or other Camera）
坚固的三脚架（Sturdy tripod）

打开Seestar App，将 Seestar 连接至移动设备（Open the Seestar App and connect Seestar to your mobile device）
进入Seestar App中的星图，在星图中搜索并寻找到 C/2023 A3（紫金山-阿特拉斯）彗星（Enter the SkyAtlas in the Seestar App, search and find Comet C/2023 A3 (Tsuchinshan-ATLAS) in the SkyAtlas）
点击GoTo开始自动拍摄（Click GoTo to start automatic shooting）

紫金山彗星：总结

Comet Tsuchinshan-ATLAS: Bottom line

C/2023 A3 (紫金山-阿特拉斯) 彗星已经可以在南半球用双筒望远镜看到，很快在北半球也能看到。到2024年10月12日左右，它的亮度可能会达到-4等，并它会成为过去100年中北半球可见的最亮彗星之一！

Comet C/2023 A3 (Tsuchinshan-ATLAS) is already visible with binoculars from the Southern Hemisphere and will soon be visible from the Northern Hemisphere. Around October 12, 2024, it could reach magnitude -4 and become one of the brightest comets visible in the Northern Hemisphere in the last 100 years!

文章转自StarWalk

观测 C/2023 A3（紫金山-阿特拉斯 Tsuchinshan-ATLAS）彗星