Errors in Measurement of the Solar Diameter in the Seventeenth and Eighteenth Centuries

Parkinson John H. Morrison Leslie V. and Stephenson Richard F. , “The constancy of the solar diameter over the past 250 years”, Nature, cclxxxviii (1980), 548–51.

Eddy J. A. and Boornazian A. A. , “Secular decrease in the solar diameter, 1863–1953”, Bulletin of the American Astronomical Society, xi (1979), 437. This is an abstract of a paper presented at the AAS 154th Meeting in Wellesley, Mass., and it created more than passing interest. Some details were published in the “Search and discovery” section of Physics today by the Senior Editor, Lubkin Gloria B. , under the title “Analyses of historical data suggest Sun is shrinking”, Physics today, xxxii (1979), 17–19, and a summary was also published in Science news, cxv (1979), 420, under the title “Is the Sun shrinking? Two views”.

Wittmann A. , “The diameter of the Sun”, Astronomy and astrophysics, lxi (1977), 225–7.

Wittmann A. , “Evidence against a secular decrease of the solar diameter”, Solar physics, lxvi (1980), 223–31.

Parkinson John , “New measurements of the solar diameter”, Nature, ccciv (1983), 518–20.

See Sofia S. O'Keefe J. Lesh J. R. and Endal A. S. , “Solar constant: Constraints on possible variations derived from solar diameter measurements”, Science, cciv (1979), 1306–8 for a review of the pre-1980 attempts. Parkinson , op. cit. (ref. 1), 551.

Ribes E. Ribes J. J. and Barthalot R. , “Evidence for a larger Sun with a slower rotation during the seventeenth century”, Nature, cccxxvi (1987), 52–55. In addition to the following two references, the results of Ribes have also been referred to in the popular literature of astronomy, without critical comment, in an article by Lief J. Robinson entitled “The sunspot cycle: The tip of the iceburg”, Sky and telescope, lxiii (1987), 589–91.

O'Dell C. A. and Van Helden A. , “How accurate were seventeenth-century measurements of solar diameter?”, Nature, cccxxx (1987), 629–31.

Morrison Leslie V. Stephenson Richard F. and Parkinson John , “Diameter of the Sun in a.d. 1715”, Nature, cccxxxi (1988), 421–3. See also Dunham David W. Sofia Sabatino Fiala Alan D. Herald David and Muller Paul M. , “Observations of a probable change in the solar radius between 1715 and 1979”, Science, ccx (1980), 1243–5. By reanalysing observations of the same solar eclipse of 3 May 1715, Morrison found virtually no change in solar diameter but Dunham found a decrease of approximately 0.34 + 0.2 arc seconds. As Dunham point out, the recorded observations are open to a degree of interpretation.

Wolf A. , Histoire de l'Observatoire de Paris (Paris, 1902), 139–40. Römer did not invent his transit telescope until 1690 though it was probably based on Picard's idea of fixing a telescope in the meridian.

Brooks G. P. and Brooks R. C. , “The improbable progenitor”, Journal of the Royal Astronomical Society of Canada, lxxiii (1979), 9–23.

Auzout A. , “Of a letter written Decemb. 28. 1666. by M. Auzout …”, Philosophical transactions of the Royal Society, ii (1667), 373–5.

Townley R. , “Of a letter, written by Mr. Richard Townley to Dr. Croon, touching the invention of dividing a foot into many thousand parts …”, Philosophical transactions of the Royal Society, ii (1667), 457–8.

Ribes , op. cit. (ref. 7), 52.

Auzout , op. cit. (ref. 12), 373.

Ibid., 374.

McKeon Robert , “Les débuts de l'astronomie de précision, I: Histoire de la réalisation du micrometre astronomique”, Physis, xiii (1971), 225–88.

Auzout , op. cit. (ref. 12), 374.

Wolf A. , A history of science, technology and philosophy in the 16th and 17th centuries, i (London, 1935), 171.

McKeon , op. cit. (ref. 17), 274–6.

Olmsted John W. , “The ‘application’ of telescopes to astronomical instruments: 1667–1669”, Isis, xl (1949), 213–25.

Brooks Randall C. , “Standard screw threads for scientific instruments, Part I: Production techniques and the Filière Suisse”, History and technology, v (1988), 59–76.

Hooke Robert , Description of the helioscopes and some other instruments (London, 1676), 129.

Woodbury Robert , History of the lathe to 1850 (Cambridge, Mass., 1961), 70.

Moxon Joseph , Mechanick exercises (London, 1703; reprinted New York, 1970), 35.

Auzout Adrien , Traite du micromètre, ou manière exacte pour pendre les diamètres des planètes et la distance entre les petites étoiles … (Paris, 1667), 6–10.

Bion Nicholas (trs. by Stone Edmund ), The construction and principal uses of mathematical instruments (London, 1972), 156–7. (A reprint of Stone's 1758 edn, itself a reprint, with added Appendix, of his 1723 edition which was based on Bion's original 1709 work.)

Smith Robert , A compleat system of opticks (London, 1738), ii, 348–9. Smith became Plumian Professor in 1716 and worked with Bradley.

de La Hire P. , “Construction d'une micromètre universel pour toutes éclipses de Soleil et de Lune et par l'observation des angles”, Mémoires de l'Académie des Sciences, 1717, 57–67.

de Lalande Jérôme , L'astronomie, ii, 3rd edn (Paris, 1792), 673–4.

Bradley James , “Directions for using the common micrometer taken from a paper in the late Dr. Bradley's hand-writing”, Philosophical transactions of the Royal Society, lxii (1772), 46–53. Nevil Maskelyne communicated this note having apparently found it among the papers of his predecessor-but-one as Astronomer Royal.

Brooks and Brooks , op. cit. (ref. 11), 12–14.

Grant Robert , A history of physical astronomy (London, 1852), 489.

Parkinson , op. cit. (ref. 1), 548.

Ibid., 549.

de Narbonne A. M. , (unpublished) Catalogue of the instrument collection of the Observatoire de Paris (Paris, 1987). This list does not contain any micrometers similar to those described by Auzout and Picard.

A complete description of the techniques of analysis of micrometers and micrometer screws used for this paper is in preparation. The techniques have been successfully used to assess precision screws used on scientific instruments of the seventeenth to the twentieth century.

Swingler D. N. , “A relationship between the Jurkevich periodogram and the Fourier transform estimator”, Astronomical journal, xc (1985), 675–9.

Daumas Maurice , Scientific instruments of the seventeenth and eighteenth centuries (New York and Washington, 1972), 50–51.

Balthasar Theodore , Micrometria sive de micrometrorum telescopiis et microscopiis applicandorum varia structura (Erlangen, 1710), 46, 50.

Price Derek J. , “The early observatory instruments of Trinity College, Cambridge”, Annals of science, viii (1952), 1–12, pp. 2–3, 12.

See Narbonne , op. cit. (ref. 36) for her description of this instrument. This 6ft sextant by Langlois was used by Lacaille at the Cape of Good Hope in 1751 (see King Henry C. , The history of the telescope (London, 1955), 106). It is of course possible that the micrometers on this instrument were replaced before Lacaille left for the Cape. Those on the Langlois quadrant of Chabert were upgraded before he left for his voyage to Louisbourg, Nova Scotia in 1750. See de Chabert , Voyage fait par ordre du roi en 1750 et 1751 dans l'Amérique septentrionale (Paris, 1753; reprinted 1966), 5; or Brooks Randall C. , “M. de Chabert and the 1750 Louisbourg observatory”, Journal of the Royal Astronomical Society of Canada, lxxiii (1979), 333–48.

Grant , op. cit. (ref. 33), 347–58.

Wittmann , op. cit. (ref. 3), 225–6.

Lalande , op. cit. (ref. 30), 117.

Grant , op. cit. (ref. 33), 355n.

Cullen R. T. , “Diameters of the Sun observed at Greenwich, 1915–1925”, Monthly notices of the Royal Astronomical Society, lxxxvi (1925/26), 344–9.

Wittmann , op. cit. (ref. 3), 225.

O'Dell and Van Helden , op. cit. (ref. 8), 629–30 and also Morrison , op. cit. (ref. 9), 423.

Ribes , op. cit. (ref. 7), 52–53.

Flamsteed did in fact use this method, having learned it from Townley in August 1672. Flamsteed described his use of the technique in detail in a letter which may be found in Bailey F. , An account of the Revd. John Flamsteed (London, 1835; reprinted London, 1966), 110.

Dunham , op. cit. (ref. 9), 1244 and Morrison , op. cit. (ref. 9), 421.