Copernicus' complex Mercury model in De revolutionibus is virtually identical, geometrically, to Ibn al-Šāṭir's (ca. 1305 – ca. 1375). However, the model in his earlier Commentariolus is different and in many ways unworkable. This has led some to claim that the younger Copernicus did not understand his predecessor's model; others have maintained that Copernicus was working totally independently of Ibn al-Šāṭir. We argue that Copernicus did have Ibn al-Šāṭir's models but needed to modify them to conform to a “quasi-homocentricity” in the Commentariolus. This modification, and the move from a geocentric to heliocentric cosmology, was facilitated by the “heliocentric bias” of Ibn al-Šāṭir's models, in which the Earth was the actual center of mean motion, in contrast to Ptolemy and most Islamicate astronomers. We show that: 1) Ibn al-Šāṭir sought to reproduce Ptolemy's critical elongation at the trines(±120°), but changed the Ptolemaic values at 0, ±90, and 180°; 2) in the Commentariolus, Copernicus does not try to produce viable elongations for Mercury; and 3) by the time of writing De revolutionibus, Copernicus is in full control of the Mercury model and is able to faithfully reproduce Ptolemy's elongations at all critical points. We also argue that claims regarding “natural” solutions undermining transmission are belied by historical evidence.

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IBN AL-ŠĀṬIR 和哥白尼的水星模型

哥白尼的复水星模型革命者在几何上，它与伊本·阿尔-Šāṭir 的（约 1305 - 约 1375 年）几乎相同。然而，他早期的模型评论是不同的，并且在许多方面是行不通的。这导致一些人声称年轻的哥白尼不了解他的前任的模型。其他人则坚持认为，哥白尼的工作完全独立于伊本 al-Šāṭir。我们认为哥白尼确实有 Ibn al-Šāṭir 的模型，但需要修改它们以符合评论. Ibn al-Šāṭir 模型的“日心偏向”促进了这一修改，以及从地心宇宙学向日心宇宙学的转变，与托勒密和大多数伊斯兰天文学家相比，地球是平均运动的实际中心。我们表明：1) Ibn al-Šāṭir 试图重现托勒密在三分相 (±120°) 处的临界伸长率，但将托勒密值更改为 0、±90 和 180°；2) 在评论，哥白尼并没有试图为水星产生可行的伸长；3) 在撰写本文时革命者，哥白尼完全控制了水星模型，并且能够在所有关键点忠实地再现托勒密的伸长率。我们还认为，关于破坏传播的“自然”解决方案的说法被历史证据所掩盖。