Annie Jump Cannon was an American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 astronomer

Astronomer

An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

 whose cataloging work was instrumental in the development of contemporary stellar classification

Stellar classification

In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme

Stellar classification

In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

, which was the first serious attempt to organize and classify stars based on their temperatures.
The daughter of shipbuilder and state senator Wilson Lee Cannon and his second wife, Mary Elizabeth Jump, Annie grew up in Dover, Delaware

Dover, Delaware

The city of Dover is the capital and second largest city in the U.S. state of Delaware. It is also the county seat of Kent County, and the principal city of the Dover, Delaware Metropolitan Statistical Area, which encompasses all of Kent County. It is located on the St. Jones River in the Delaware...

.