The eighth-century Latin manuscript Milan, Veneranda Biblioteca Ambrosiana, L 99 Sup. contains fifteen palimpsest leaves previously used for three Greek scientific texts: a text of unknown authorship on mathematical mechanics and catoptrics, known as the Fragmentum Mathematicum Bobiense (three leaves), Ptolemy's Analemma (six leaves), and an astronomical text that has hitherto remained unidentified and almost entirely unread (six leaves). We report here on the current state of our research on this last text, based on multispectral images. The text, incompletely preserved, is a treatise on the construction and uses of a nine-ringed armillary instrument, identifiable as the “meteoroscope” invented by Ptolemy and known to us from passages in Ptolemy's Geography and in writings of Pappus and Proclus. We further argue that the author of our text was Ptolemy himself.

八世纪拉丁手稿米兰，Veneranda Biblioteca Ambrosiana，L 99 Sup。包含十五张重写本的叶子，以前用于三本希腊科学文本：作者身份不明的数学力学和反射光学文本，称为 Fragmentum  Mathematicum Bobiense  （三页）、托勒密的 Analemma  （六页），以及迄今为止身份不明的天文文本几乎完全未读（六页）。我们在此报告基于多光谱图像的最后一篇文章的研究现状。该文本保存不完整，是一篇关于九环浑仪的构造和使用的论文，可确定为托勒密发明的“气象仪”，我们从托勒密的地理学段落中 得知 以及 Pappus 和 Proclus 的著作。我们进一步论证，我们文本的作者是托勒密本人。