In 1717, Halley compared contemporaneous measurements of the latitudes of four stars with earlier measurements by ancient Greek astronomers and by Brahe, and from the differences concluded that these four stars showed proper motion. An analysis with modern methods shows that the data used by Halley do not contain significant evidence for proper motion. What Halley found are the measurement errors of Ptolemaios and Brahe. Halley further argued that the occultation of Aldebaran by the Moon on 11 March 509 in Athens confirmed the change in latitude of Aldebaran. In fact, however, the relevant observation was almost certainly made in Alexandria where Aldebaran was not occulted. By carefully considering measurement errors, Jacques Cassini showed that Halley’s results from comparison with earlier astronomers were spurious, a conclusion partially confirmed by various later authors. Cassini’s careful study of the measurements of the latitude of Arcturus provides the first significant evidence for proper motion.

中文翻译：

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为什么哈雷没有发现正确的运动，为什么卡西尼号发现了

1717 年，哈雷将四颗恒星纬度的同期测量值与古希腊天文学家和布拉赫的早期测量值进行了比较，从差异中得出的结论是，这四颗恒星显示了自己的运动。现代方法的分析表明，哈雷使用的数据不包含自行运动的重要证据。Halley 发现的是 Ptolemaios 和 Brahe 的测量误差。哈雷进一步认为，509 年 3 月 11 日在雅典被月球掩星的毕宿五确认了毕宿五的纬度变化。然而，事实上，相关的观察几乎肯定是在亚历山大港进行的，那里没有隐匿毕宿五。通过仔细考虑测量误差，雅克·卡西尼表明哈雷与早期天文学家的比较结果是虚假的，后来的许多作者都部分证实了这一结论。卡西尼号对大角星纬度测量的仔细研究为自行提供了第一个重要证据。