In this paper, we discuss Babylonian observations of a “massing of the planets” reported in two Astronomical Diaries, BM 32562 and BM 46051. This extremely rare astronomical phenomenon was observed in Babylon between 20 and 30 March 185 BC shortly before sunrise when all five planets were simultaneously visible for about 10 to 15 min close to the horizon in the eastern morning sky. These two observational texts are not only interesting as records of an extremely rare planetary configuration, but also because (1) the observers appear to be confused by the presence of all planets simultaneously and mix them up in their reports, and (2) the two reports of the same observations are so different that we are forced to conclude that they were carried out by two different observers. There is an additional astronomical event which makes this planetary configuration even more unique: the exact conjunction of the planets Mars and Jupiter in the afternoon of 25 March 185 BC. An exact conjunction, where two planets are so close together that they appear as one object in the sky, is also extremely rare. Although this exact conjunction between Mars and Jupiter occurred during the day so that it was not observable, it was correctly predicted by the Babylonian scholars: a remarkable achievement and a nice illustration of their astronomical craftsmanship. Finally, our study clearly exposes one of the limitations of Babylonian naked-eye astronomy. When first appearances of the planets Mercury, Mars and Saturn are expected around the same date, it is nearly impossible to correctly identify them because their expected positions are only approximately known while they have about the same visual magnitude so that they become visible at about the same altitude above the horizon.

中文翻译：

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巴比伦对独特行星结构的观察

在本文中，我们讨论了巴比伦人对两本天文日记 BM 32562 和 BM 46051 中报道的“行星聚集”的观测。这种极为罕见的天文现象是在公元前 185 年 3 月 20 日至 30 日期间在巴比伦观测到的，当时所有五个在东部早晨的天空中，靠近地平线的地方同时可以看到行星大约 10 到 15 分钟。这两个观测文本不仅有趣，因为它记录了极其罕见的行星配置，还因为 (1) 观测者似乎对所有行星同时存在感到困惑，并在他们的报告中将它们混为一谈，以及 (2) 两者相同观察的报告是如此不同，以至于我们不得不得出结论，它们是由两个不同的观察者进行的。还有一个额外的天文事件使这个行星配置更加独特：火星和木星在公元前 185 年 3 月 25 日下午的确切会合。两颗行星靠得很近以至于它们在天空中显示为一个物体的精确合相也极为罕见。尽管火星和木星之间的这种确切合相发生在白天，因此无法观察到，但巴比伦学者正确预测了这一点：这是一项了不起的成就，也是他们天文工艺的一个很好的例证。最后，我们的研究清楚地揭示了巴比伦裸眼天文学的局限性之一。当水星、火星和土星首次出现在同一天时，