Related papers: An astronomical analysis of Hipparchus' Commentari…

The uncertainty about the relationships between the star catalogue contained in the Almagest (books VII-VIII) and the catalogue of Hipparchus dates back to the origins of modern astronomy. The fact that Hipparchus' catalogue was lost and…

This paper summarises briefly and in English some of the results of the book Hoffmann: Hipparchs Himmelsglobus, Springer, 2017 that had to be written in German. The globe of Hipparchus is not preserved. For that reason, it has been a source…

A re-investigation of the parapegma of Euktemon (5th century BC, Athens), based on the assumption that some star observations may in fact have been calculated rather than directly observed. The calculation follows Pliny, Natural History…

In this article I discuss the fragments of Hipparchus' star catalogue and compare them to Hipparchus' Exegesis to trace the early history of stellar catalogues in Greek astronomy.

This is the first translation of Hipparchus Commentaries on the Phenomena of Aratus and Eudoxus into a modern language since the one, in German, published by the philologist Karl Heinrich August Manitius in 1894. Published in 2013, it is…

The great development of astrometric accuracy since the observations by Hipparchus about 150 BC was documented in 2008 in the first version of the present report. This report was updated in H{\o}g (2017d), e.g. with recent information on…

The great development of astrometric accuracy since the observations by the Greek astronomer Hipparchus about 150 BC has often been displayed in diagrams showing the accuracy versus time. Two new diagrams are provided here, one for…

The modern usage of the words astronomy and astrology is traced back to distinctions, largely ignored in recent scholarship. Three interpretations of celestial phenomena (in a geometric, a substantialist and a prognostic versions) coexisted…

Ancient astronomers faced the problem of dealing with arcs and angles in their observations and predictions without the help of modern trigonometry. The usual method to deal with such problems was the Menelaus Theorem, explicitly discussed…

In Plato's dialogues Republic and Laws, the most important disciplines for the best education of the rulers of the city are identified with arithmetic, geometry and astronomy. Those disciplines, however, are not intended for practical…

If one wants to translate the heliocentric picture of planets moving uniformly on circular orbits about the sun to the perspective of a terrestrial observer, using classical (ancient) geometric means only, one is naturally led to the…

Many have have taken in hand to write a treatise on the Star of Bethlehem, particularly on Kepler's explanation as a stellar birth, triggered by Mars joining a great conjunction (a meeting of Jupiter and Saturn), as he observed it in…

The Anthologies of the second-century astrologer Vettius Valens (120-c.175 CE) is the most extensive surviving practical astrological text from the period. Despite this, the theoretical underpinnings of the Anthologies have been…

Tycho Brahe, the most prominent and accomplished astronomer of his era, made measurements of the apparent sizes of the Sun, Moon, stars, and planets. From these he showed that within a geocentric cosmos these bodies were of comparable…

Johannes Kepler described the Copernican universe as consisting of a central, small, brilliant sun with its planetary system, all surrounded by giant stars. These stars were far larger than, and much dimmer than, the sun -- his De Stella…

The early Greek and Indian cosmologies are summarized in this paper. The two traditions appear to have developed independently although after the time of Alexander they were consciously aware of each other. The focus and style of the two…

Here follow three reports covering different aspects of the early history from 1964 to 1980 of the Hipparcos satellite mission. The first report "Interviews about the creation of Hipparcos" contains interviews from 2017 with scientists…

In this brief article I review the history of astronomical photometry, touching on observations made by the ancient Chinese, Hipparchus and Ptolemy, the development of the concept (and definition) of magnitude, the endeavors of Argelander…

The satellite missions Hipparcos and Gaia by the European Space Agency will together bring a decrease of astrometric errors by a factor 10000, four orders of magnitude, more than was achieved during the preceding 500 years. This modern…

Leonhard Euler, the most prolific mathematician in history, contributed to advance a wide spectrum of topics in celestial mechanics. At the Saint Petersburg Observatory, Euler observed sunspots and tracked the movements of the Moon.…