The collection of papers assembled here on a variety of topics in ancient and medieval astronomy was originally suggested by Noel Swerdlow of the University of Chicago. He was also instrumental in making a selection* which would, in general, be on the same level as my book The Exact Sciences in Antiquity. It may also provide a general background for my more technical History of Ancient Mathematical Astronomy and for my edition of Astronomi cal Cuneiform Texts. Several of these republished articles were written because I wanted to put to rest well-entrenched historical myths which could not withstand close scrutiny of the sources. Examples are the supposed astronomical origin of the Egyptian calendar (see [9]), the discovery of precession by the Babylonians [16], and the "simplification" of the Ptolemaic system in Copernicus' De Revolutionibus [40]. In all of my work I have striven to present as accurately as I could what the original sources reveal (which is often very different from the received view). Thus, in [32] discussion of the technical terminology illuminates the meaning of an ancient passage which has been frequently misused to support modern theories about ancient heliocentrism; in [33] an almost isolated instance reveals how Greek world-maps really looked; and in [43] the Alexandrian Easter computus, held in awe by many historians, is shown from Ethiopic sources to be based on very simple procedures.

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This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Excerpt from Astronomical Essays Historical and Descriptive The Secular Variation of Stars, The Number of the Visible Stars, and The Satellite of Sirius. The rest have not been hitherto published. For much of the information contained in the first three essays, and in N os. 7 and 8, I am indebted to Houzeau and Lancaster's Bibliographic Générale de i'astronomie, vol. I., Introduction. For the illustrations, my best thanks are due to Professor Barnard, B.se., of the Yerkes Observatory and to Dr. Max Wolf, of Heidelberg. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.