Discovered the relation between the period and luminosity of classical Cepheid variable stars. This period-luminosity (P-L) relation made possible measurement of the distances of stars from the earth and the determinationof intergalactic distances by determining the distances from the earth of stars in galaxies outside our own. This relation remains of great importance in the determination of astronomical distances.

Observations that determined absolute photographic magnitudes (brightness) of a sequence of 47 star near the North Pole that could then be used as a standard of comparison to measure the absolute magnitudes (brightness) of other stars.

Discovered 1,777 variable stars in the Magellanic Clouds.

"Periods of 25 Variable Stars in the Small Magellanic Cloud," Harvard College Observatory Circular 173 (1912).

"Standard Photographic Magnitudes," Science 30:726 (1909).

"1777 Variables in the Magellanic Clouds", Annals of Harvard College Observatory 15: 87 (1908)

Honorary Member, American Association of Variable Star Observers

Jobs/Positions

1902-1921 Staff Member, Harvard College Observatory

Head, Department of Photographic Photometry

B.A. Radcliffe College 1892

References consulted

[1N N20], [5A1 DSB], [7 MWR1], [8 MBO], [9C NAW], [54 JSB], [51 MJB], [29 WWWS], [12D GKS],[www.eb.com]

"The standard of photographic measurements that she evolved was accepted generally among the astonomers of the world, and it was known as the Harvard Standard." [51 MJB]

Field Editor: Professor Jean Turner