Skip to main content

Chandler, Seth Carlo

Chandler, Seth Carlo

(b. Boston, Massachusetts, 17 September 1846; d. Wellesley Hills, Massachusetts, 31 December 1913),


Chandler was educated at the English High School in Boston. After graduation (1861) he became private assistant to Benjamin Apthorp Gould and involved with the U.S. Coast Survey, which he joined in 1864. Rather than accompany Gould to Argentina, Chandler worked for many years as an actuary and did not resume his scientific activities until 1881.

He then became associated with the Harvard College observatory, evolving with J. Ritchie the Science Observer Code (1881), a system for transmitting by telegraph information about newly discovered comets. Chandler published many papers on comets and variable stars and compiled several useful catalogs of the latter objects.

His most important contribution to science was the discovery of the variation of latitude. Soon after arriving at Harvard, Chandler devised the almucantar, an instrument by means of which one relates positions of stars not to the meridian but to a small circle centered at the zenith. In his discussion (1891) of observations made with this instrument during 1884–1885 he concluded that the latitude varied with amplitude 0″.3 in a period of fourteen months. Observations made about the same time in Berlin by Kü st-ner had shown a similar variation. From an exhaustive rediscussion of observations made as far back as Bradley’s time, Chandler was able to verify the fourteen-month period and to show that there was in addition a variation having a period of twelve months. His announcements met with considerable opposition, initially because Euler had shown that any variation would have a period of ten months; but as Newcomb pointed out, since the earth is not completely rigid, the period would be longer.

Chandler was editor of the Astronomical Journal from 1896 to 1909 and subsequently an associate editor. He received an LL. D. degree from DePauw University (1891), the Watson Medal of the National Academy of Sciences (1895), and the Gold Medal of the Royal Astronomical Society (1896).


Chandler’s “On the Variation of Latitude” is in Astronomical Journal11 (1891), 59–61, 65–70. 75–79, 83– 86;12 (1892), 17–22,57–62, 65–72,97–101; 13 (1893). 159– 162. Chandler’s many papers in the Astronomical Journal are listed in the General Index to the Journal, 1–50 (1948), 15–17.

Chandler is discussed in H, H. Turner. Astronomical Discovery (London, 1904), pp. 177–217. See also Turner’s obituary notice of Chandler in Monthly Notices of the Royal Astronomical Society, 75 (1915), 251–256.

Brian G. Marsden

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Chandler, Seth Carlo." Complete Dictionary of Scientific Biography. . 19 Jan. 2019 <>.

"Chandler, Seth Carlo." Complete Dictionary of Scientific Biography. . (January 19, 2019).

"Chandler, Seth Carlo." Complete Dictionary of Scientific Biography. . Retrieved January 19, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.