(b. Dordrecht, Netherlands, 10 September 1864; d. The Hague, Netherlands, 3 June 1929)
The son of J. J. Easton, a sailor, and M. W. Ridderhof, Easton was principally a journalist. After graduating from high school in 1881, he first attended courses for those wishing to become government employees in Indonesia (then under Dutch rule) and subsequently studied French at the Sorbonne until 1886. After a short period of teaching, he became associated with various newspapers, notably the Nieuwe Rotterdamsche Courant (1895–1906), the Nieuws uan den Dag of Amsterdam (1906–1923), and the Haagsche Post (from 1923).
Easton’s contributions to astronomy deal mostly with the description and interpretation of the Milky Way. At the age of seventeen, as an amateur astronomer, he made his first drawings of the distribution of its brightness. The subsequent perfection and Easton’s interpretation of these drawings gained him international fame and, in 1903, an honorary doctorate in physical sciences from the University of Groningen, at the proposal of the famous astronomer J. C. Kapteyn. The drawings aimed, first of all, at the representation of the northern Milky Way as a whole; detailed descriptions of certain regions of the sky published by such authors as He is and Otto Boeddicker did not allow the construction of a homogeneous overall picture. The drawings were first published at Paris in 1893, under the title La Voie Lactée, dans l’hémisphère boréal.
Subsequent work deals with the comparison of those drawings with the distribution of the stars, and with the problem of the structure of the Milky Way stellar system. Counts of the faint stars in the Bonner Durchmusterung (around ninth-magnitude) revealed close correlation between their distribution in the sky and the drawings. In his attempts to interpret these findings, Easton adopted the hypothesis that the Milky Way system resembles other celestial objects showing spiral structure, and he proposed various solutions putting the center of the galaxy in the direction of the constellation Cygnus. The work is synthesized in “A Photographic Chart of the Milky Way and the Spiral Theory of the Galactic System,” in The Astrophysical Journal (37 [March 1913]). This concept of the galactic spiral structure has not survived subsequent research, which has led to the establishment of the galactic center in the direction of Sagittarius. But Easton’s work inspired, and was highly esteemed by, such contemporary professional astronomers as Kapteyn, Pannekoek, and Seeliger.
Easton was active in many other fields of science besides astronomy. Particular mention should be made of his efforts in climatology. His monumental work Les hivers dans l’Europe occidentale (Leiden, 1928) contains a statistical-historical study of the climatological conditions in western Europe that attempts to connect data as far back as the thirteenth century with modern ones and critically studies suggested periodic variations. His accomplishments in this field led to Easton’s appointment to the Board of Curators of the Netherlands Meteorological Institute in 1923.
Easton’s principal communications or astronomical studies, apart from those cited in the text, are in the publications of the Royal Netherlands Academy of Sciences (Amsterdam), The Astrophysical Journal, Astronomische Nachrichten, and Monthly Notices of the Royal Astronomical Society.
For descriptions of Easton’s life and works see an article by J. J. Beyermann, in Nieuwe Rotterdamsche Courant (10 Sept. 1964); and J. Stein, “C. Easton in Memoriam,” in Hemel en Dampkring (July, Aug.–Sept. 1929).