Ritchey,Curtis and the Discovery of Novae in Spiral Nebulae

See Berendzen Richard and Hoskin Michael , “Hubble's Announcement of Cepheids in Spiral Nebulae”, Astronomical Society of the Pacific leaflet no. 504 (June 1971). Hubble's achievement was known to astronomers well before the formal announcement on 1 January 1925.

Herschel William , “Account of some Observations tending to investigate the Construction of the Heavens”, Philosophical transactions, lxxiv (1784), 437–51. See Hoskin M. A. , William Herschel and the construction of the heavens (London, 1963), chap. 3.

See Hoskin M. A. , “Apparatus and Ideas in Mid-nineteenth-century Cosmology”, Vistas in astronomy, ix (1967), 79–85, pp. 80–83.

Mayall N. U. , “Edwin Hubble, Observational Cosmologist”, Sky and telescope, xiii (1953–54), 78–85.

Letter from Hubble to Harlow Shapley, 19 February 1924 (Hubble Archives, Huntington Library).

Jones Glyn Kenneth , “S Andromedae, 1885”, above, 27–40.

Clerke Agnes M. , The system of the stars (London, 1890), 370.

Reynolds J. H. writing on “Star Clusters and Nebulae” in Hutchinson's Splendour of the heavens, ed. by Phillips T. E. R. (2 vols, London, 1923), 571.

Harvard College Observatory circular no. 4 (20 December 1895).

Ibid.

Slipher V. M. , “The Radial Velocity of the Andromeda Nebula”, Lowell Observatory bulletin no. 58 (1913). The result was communicated privately to a number of astronomers early in the year.

Letter of Duncan J. C. to Slipher V. M. , 17 February 1913 (Lowell Observatory Archives).

Slipher V. M. , “The Radial Velocity of the Andromeda Nebula”, draft of Lowell Observatory bulletin no. 58 (Lowell Observatory Archives).

Hubble Edwin , The realm of the nebulae (New Haven, 1936), 85. Allan Sandage similarly gives priority to Ritchey in The Hubble atlas of galaxies (Washington, D.C., 1961), 2.

Hubble , The realm of the nebulae, 84.

Struve Otto and Zebergs Velta , Astronomy of the twentieth century (New York, 1962), p. 2 of endpapers.

Harvard College Observatory bulletin no. 641 (28 July 1917).

Ibid., and Curtis H. D. , “New Stars in Spiral Nebulae”, Publications of the Astronomica Society of the Pacific, xxix (1917), 180–2.

Observatory, xl (1917), facing p. 456.

Keeler's own programme was completed by Perrine C. D. , “Photographs of Nebulae and Clusters, Made with the Crossley Reflector, by James Edward Keeler, Director of the Lick Observatory, 1898–1900”, Publications of the Lick Observatory, viii (1908), 1–46 with 70 plates.

Curtis Heber D. , “Changes in the Mounting of the Crossley Reflector”, Publications of the Astronomical Society of the Pacific, xxii (1910), 40–41, and further papers in vols xxv (1913), 265–6 and xxvi (1914), 46–51.

Curtis H. D. , “Report of Work from July 1, 1912, to July 1, 1913”, draft in Lick Observatory Archives.

Curtis H. D. , “Report 1913, July 1–1914, May 15”, draft in Lick Observatory Archives. He refers to “the existence of exceedingly high radial velocities among the nebulae”, and these may have decided Curtis in favour of the view that the spirals are galaxies.

“Edgewise or Greatly Elongated Spirals”, draft list by Curtis, Lick Observatory Archives.

Lick Observatory Archives.

For example, his letter to Shapley of 31 July 1917 cited below.

Curtis Heber D. , “Three Novae in Spiral Nebulae”, Lick Observatory bulletin no. 300 (drafted 8 September 1917 and issued 16 October) 108.

Ibid., and Curtis , “New Stars in Spiral Nebulae” (ref. 18), 181.

Curtis , “New Stars in Spiral Nebulae” (ref. 18). The draft must have been amended to embody his further conclusions on NGC 4321, as the letters to Shapley discussed in this paragraph show.

Original in Shapley Archives, Harvard University.

Original in Shapley Archives, Harvard University. Curtis also wrote the same day to Slipher, informing him of his discovery of three novae and asking if Slipher had plates of the nebulae concerned (original in Lowell Observatory Archives); Slipher sent five plates of NGC 4321 but they were of little use as they were of only eight minutes' exposure. A third letter with the news of NGC 4321 was sent to Pickering E. C. at Harvard and incorporated in Harvard College Observatory bulletin no. 642 (9 August 1917).

Ref. 27. Correspondence between Campbell and Curtis now in the Lick Observatory Archives show that the Bulletin was written under difficulties as Curtis was away on war work at San Diego. The concluding paragraph, offering “another way” of establishing the distances of spirals from the novae contained in them, was inserted by Campbell with no more than acquiescence by Curtis.

See for example the reports in the October 1917 issue of Publications of the Astronomical Society of the Pacific (vol. xxix, no. 171), 210–17, and the remarks on novae by Phillips T. E. R. in “Report of the Council to the Ninety-eighth Annual General Meeting”, Monthly notices of the Royal Astronomical Society, lxxviii (1917–18), 309. Phillips declares: “The Novae must almost certainly be in the nebulae, and this circumstance, taken in conjunction with the well-known clustering of Novae in our galaxy towards the galactic plane, seems highly significant, and gives striking support to the theory that the spirals are ‘island universes’”.

In the published version of the so-called “Great Debate” ( Shapley H. and Curtis H. D. , “The Scale of the Universe”, Bulletin of the National Research Council, ii, Part 3 (May 1921), 215).

Curtis , “Three Novae in Spiral Nebulae” (ref. 27), 109.