Article ID: CBB583226963

Systematic errors in Galileo's astronomical observations and alleged anomalies in the position of Neptune (2022)


In 1980 Kowal and Drake found that in December 1612 and January 1613 Galileo observed the planet Neptune. At that time, according to these authors, Galileo was able to measure angular separations with an accuracy of about 10 seconds of arc. However, as noticed by Kowal and Drake, the position of Neptune reported by Galileo is wrong with respect to the position computed with the modern ephemeris of about 1 minute of arc. This led Kowal and Drake to speculate on the possible errors of modern ephemeris of Neptune and sparked some debate about Neptune's ephemeris and/or possible errors in Galileo's measures. Until today this anomaly has remained without a conclusive answer. Here we show that, in addition to the random errors, there are other significant measurement errors present in Galileo's observations. These errors may help clarify the origin of the alleged anomalies in the position of Neptune.

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Authors & Contributors
Graney, Christopher M.
Aït-Touati, Frédérique
Case, Stephen
Débarbat, Suzanne
Dumont, Simone
Fontana, Francesco
Journal for the History of Astronomy
Journal of Astronomical History and Heritage
Physics in Perspective
Apeiron: Journal for Ancient Philosophy and Science
Galilæana: Journal of Galilean Studies
History of Science
Greenwood Press
Reaktion Books
Sally Beaumont
Walker & Company
Orange Mountain Music
Solar system; planets
Celestial mechanics
Motion (physical)
Galilei, Galileo
Hooke, Robert
Kepler, Johannes
Copernicus, Nicolaus
Einstein, Albert
Time Periods
17th century
19th century
18th century
20th century
16th century
20th century, early
Great Britain
Rome (Italy)
Rossiiskaia Akademiia Nauk

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