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The Pre-Discovery Observations of Uranus

Published online by Cambridge University Press:  12 April 2016

Eric G. Forbes
Eric G. Forbes*
Affiliation:
University of Edinburgh

Extract

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In his Astronomisches Jahrbuch for 1784, Johann Elert Bode summarises the scanty information that had reached Berlin concerning the recent discovery on 13 March 1781 of a new heavenly body by a still-unidentified observer in England. Its easterly progress through the Milky Way during the interim six months had been parallel to the ecliptic, and thus entirely consistent with the view - hitherto based only upon its brightness and clearly-defined disc - that it was a planet and not a comet. Bode therefore asks why this sixth-magnitude object had not been previously detected, and raises the question of whether it had in fact been observed by earlier astronomers but misidentified as a star. He himself had already scanned the star-catalogues of Tycho Brahe, Johann Hevelius, John Flamsteed, and Tobias Mayer; and had come to suspect that a missing sixth magnitude star in the constellation Capricorn, observed by Tycho on 20 November 1589, might have been the planet. A second possibility which still required investigation was Mayer’s star No. 964, observed in Aquarius on 25 September 1756.

Type
History of the Discovery of Uranus
Information
International Astronomical Union Colloquium , Volume 60: Uranus and the Outer Planets , 1982 , pp. 67 - 80
Copyright
Copyright © Cambridge University Press 1982

References

Notes

1. Astronomisches Jahrbuch für das Jahr 1784 nebst einer Sammlung der neuesten in die astronomischen Wissenschaften einschlagenden Abhandlungen, Beobachtungen und Nachrichten. Mit Genehmhaltung der KSnigl. Akademie der Wissenschaften berechnet und herausgegeben von J.E. Bode, Astronom der Akademie (Berlin, 1781). The abbreviated title of this periodical, adopted below, is Astr.Jahrb.

2. “Ueber einen im gegenwärtigen 1781sten Jahre entdeckten beweglichen Stern, den man für einen jenseits der Saturnsbahn laufenden, und bisher noch unbekannt gebliebenen Planeten halten kann”, ibid., pp.210-20. In a footnote on p.211 of this article, Bode gives the following five variants of Herschel’s surname that had appeared in the early French and English reports of the discovery: Mersthel, Hertschel, Herthel, Herrschell, and Hermstel.

3. Ibid., p.218.

4. Brahe, T. Historia coelestis jussu S.C.M. Ferd. III. edita complectens Observationes Astronimicas Varias ad historiam coelestem spectantes (Augustae Vindelicorum, 1666).Google Scholar

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6. Flamsteed, J. Historia Coelestis Britannicae, 3 vols. (Londini, 1725).Google Scholar

7. Mayer, T. “Fixarum zodiacalium catalogus novus ex observationibus Gottingensibus ad initium anni 1756 constructus”, in Lichtenberg, G.C. (ed.), Opera inedita Tobiae Mayeri I (Gottingae, 1775), pp.49–74.Google Scholar

8. Ibid., p.72

9. Astr.Jahrb. für 1785 (Berlin, 1782), p.189.

10. The circumstances which resulted in this arrangement being made are described in the introduction to Forbes, E.G. (ed.) Tobias Mayer’s Opera Inedita (London, 1971), p.12.Google Scholar

11. Op.cit., note 7.

12. “Aus einen Schreiben des Herrn Prof. Lichtenberg an Herrn Hofrath KSstner, vom 1. Sept. 1781”, op.cit., note 9, p.192.

13. Ibid., p.190.

14. “Aus einem Schreiben des Herrn Herschel an mien” (London, 13 August 1783), in Bode’s Astr.Jahrb. far 1786 (Berlin, 1783), p.258.

15. Méchain to Bode; Paris, 1 April 1784, in Bode’s Astr.Jahrb. für 1787 (Berlin, 1784), p.141.

16. Bode, J.E., “Fortgesetzte Bemerkungen über den neuen Planeten (Uranus)” in op.cit., note 14, pp.219–23.Google Scholar

17. Op.cit., note 18, p.246.

18. Bode, J.E., “Versuch eines Beweises, dass bereits Flamsteed im Jahr 1690 (so wie Tobias Mayer im Jahr 1756) den neuen Planeten beobachtet”, Astr.Jahrb. für 1787 (Berlin, 1784), pp.243–6.Google Scholar

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20. “Astronomische Beobachtungen und Nachrichten, von Herrn Prof. von Zach. Aus zweyen Briefen desselben an mich”, Bode’s Astr. Jahrb. für 1788 (Berlin, 1785), pp.214-20. In a letter of 21 May 1785, von Zach told Bode that the Graf von Brühl, de Luc, Aubert, and himself had all spent a night with Herschel at Datchet, discussing this and other matters; during which time, Herschel had expressed the opinion that 34 Tauri was “very probably the new planet” (ibid., p.214).

21. Op.cit., note 18, p.246.

22. Fixlmillner, P., “Untersuchung der Elemente der wahren Laufbahn des neuen Planeten”, ibid. Google Scholar

23. Op.cit., note 20, pp.214-15.

24. Fixlmillner, P., “Ueber die Tafeln vom Uranus und neue Elemente der Bahn dieses Planeten”, Bode’s Astr.Jahrb. für 1792 (Berlin, 1789), pp.158–60.Google Scholar

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26. This would seem to be contradicted by Francis Baily in his introductory remarks on “Mayer’s Catalogue of Stars”, Memoirs of the Royal Astronomical Society 4 (1831), 395-6.

27. Zach, F.X. von “Versuch einer geschichtlichen Darstellung der Fortschritte der Sternkunde im verlorenen Decennio”, Monatliche Correspondem zur Bef&rderung der Erd- und Himmels-Kunde 23 (1811), 205–56 Google Scholar. See p.221.

28. Op.cit., note 25, p.20.

29. Op.cit., note 6; vol.2, p.86.

30. Astr.Jahrb. für 1793 (Berlin, 1790), p.20.

31. Lalande, J.J. de, Histoire Celeste Française, contenant les observations faites par plusieurs astronomes français 1 (Paris, 1801), p.188.Google Scholar

32. Burckhardt, J.C., “Sur plusieurs observations de la planète Uranus qu’on trouve parmi les étoiles de Flamsteed”, Connaissance des Tems, ou des mouvemens célestes, I l’usage des astronomes et des navigateurs, pour l’an 1820 (1818), 408–9.Google Scholar

33. Bouvard, A., “Extrait des registres des observations astronomiques faites par Lemonnier, à l’Observatoire des Capucins, rue Saint-Honoré, a Paris”, ibid, pour l’an 1821 (1819); Additions, 339–47.Google Scholar

34. Burckhardt, J.C., “Sur l’opposition d’Uranus en 1715, et sur les résultats qu’on peut en tirer”, loc.cit., note 32, 410–12.Google Scholar

35. Ibid.; footnote, p.410.

36. La Caille, N.L. de, Coelum Australe Stelliferum (Paris, 1.763)Google Scholar. This catalogue contained a selection from a total of approximately 10,000 stars observed over a period of nineteen months at the Cape of Good Hope. The star-positions in it were later adjudged by Baily, Francis (Monthly Notices of the Royal Astronomical Society 5 (1833), 93)Google Scholar to be reliable only to within + 30”.

37. Herschel, C. Catalogue of Stars, taken from Mr. Flamsteed’s observations … and not inserted in the British Catalogue … With … remarks by William Herschel (London, 1798).Google Scholar

38. op.cit., note 34, p.412.

39. Op.cit., note 33, p.341.

40. Bessel, F.W. Fundamenta Astronomiae pro Anno MDCCIV deductaex Observationibus viri incomparabilis James Bradley in Specula Astronomica Grenovicensi per Annos 1750-1762 institutis (Regiomonti, 1818), p.283.Google Scholar Mayer’s observation of 25 September 1756 is reduced by Bessel on pp.284-5.

41. Breen, H., “On early Observations of Uranus by Bradley”, Monthly Notices of the Royal Astronomical Society 24 (1864), 124–5.Google Scholar

42. These are discussed by their author in the second part of the introduction to his Tables Astronomiques publiées par le Bureau des Longitudes de France, contenant les Tables de Jupiter, de Saturne et d’Uranus, construites d’après la Théorie de la Méchanique céleste (Paris, 1821).

43. Lexell, A.I. “Recherches sur la nouvelle Planète découverte par M. Herschel & nommée par lui Georgium Sidus”, Nova Acta Academiae Scientiarum Imperialis Petropolitanae, I (1787), 78 and 79.Google Scholar

44. Briefwechsel zwischen Gauss und Bessel herausgegeben auf Veranlassung der Königlich Preussischen Akademie der Wissen-schaften (Leipzig, 1880), p.435.

45. Bessel, F.W., “Ueber die Verbindung der astronomischen Beobachtungen mit der Astronomie”, in Schumacher, H.C. (ed.), Populare Vorlesungen über wissenschaftliche GegenstSnde (Hamburg, 1848), p.452.Google Scholar

46. Adams, J.C., “An Explanation of the Observed Irregularities in the Motion of Uranus”, Memoirs of the Royal Astronomical Society 16 (1847), 429.Google Scholar

47. Bessel to Gauss; Konigsberg, 8 November 1843, op.cit., note 44 p.567.

48. Adams, J.C. “On the Perturbations of Uranus”, The Nautical Almanac and Astronomical Ephemeris for the Year 1851, with an Appendix (London, 1847), pp.265–93.Google Scholar

49. Monthly Notices of the Royal Astronomical Society 7 (1847), 121-52.

50. ibid., p.131.

51. Le Verrier, U.-J.J., “Recherches sur les Mouvements de la Planète Herschel, dite Uranus”, Connaissance des Temps … pour l’An 1849 (Paris, 1846)Google Scholar; Additions, pp.1-254.

52. Detailed accounts of the circumstances surrounding this discovery are contained in Alexander, A.F.O’D., The Planet Uranus (London, 1965)Google Scholar and Grosser, Edward M., The Discovery of Neptune (Cambridge, Mass., 1962).Google Scholar

53. Op.cit., note 51, p.126. A table in ibid., p.129 contains the corrected mean times (based on the Paris meridian), the observed and calculated equatorial co-ordinates, and the residual differences in both these and the ecliptic coordinates.

54. This is taken from Edgar W. Woolard, “Comparison of the Observations of Uranus previous to 1781 with theoretical positions obtained by numerical integration”, The Astronomical Journal 57 (1952), 35-38. Compare his Table 1, p.36 with that in Le Verrier, op.cit., note 51, p.129.

55. Newcomb, S., “An Investigation of the Orbit of Uranus, with general Tables of its Motion”, Smithsonian Contributions to Knowledge No. 262, vol.19 (Washington [D.C.], 1874).Google Scholar

56. Safford, T.H., “On the Perturbations of Uranus and the Mass of Neptune”, Monthly Notices of the Royal Astronomical Society 22 (1862), 142–4.CrossRefGoogle Scholar

57. Op.cit., note 54, p.37.

58. This can be appreciated by an inspection of the results of Newcomb’s reductions of Flamsteed’s observations; namely, for cases 1, 3, 4, 5 in Table II: -0?8, +5”; -0?1, -6”; +0?9. +2”; and -1?5, +10” respectively.

59. Rawlins, D., “A Long Lost Observation of Uranus: Flamsteed, 1714”, Publications of the Astronomical Society of the Pacific 80 (1968), 217–19.CrossRefGoogle Scholar