African-American Pioneers in Science

Benjamin Banneker (1731 - 1806)

Benjamin Banneker Photo
Photo Credit: Wikimedia Commons

Astronomer, Mathematician and Inventor


Oella, Maryland



  • Benjamin Banneker
  • Accomplished astronomer skilled at making astronomical calculations and observations.
  • Published yearly (1791 - 1797) almanacs with a variety of information including an ephemeris, sunrise & sunset times, tides, and weather forecasts.
  • Built first American made clock (carved from hardwood) and became an expert in clock making.

Astronomer and mathematician Benjamin Banneker was born on November 9, 1731 in Oella, Maryland. His maternal grandmother, Molly Welsh, was born in England and came to America as an indentured servant. Once freed, she bought a tobacco farm and married Bannaka, one of her former slaves. Upon their marriage Bannaka's name was Anglicized to Banneker. Their daughter Mary, Banneker's mother, married Banneker's father, Robert, a former slave who had gained his freedom.

Banneker had little formal education and learned to read and write from his grandmother Molly but armed with only this basic education, the young Banneker soon was able to learn anything that caught his interest.

In 1753, when he was 22, he met a man who owned a pocket watch. During this period in colonial times, watches and other timepieces were rare. Banneker was fascinated with the watch and after studying its inner workings, set out to construct a clock. He made mathematical calculations to determine the size of the gears and number of teeth in each necessary for the clock to keep accurate time. Lacking the resources to buy metal castings, he carved most of the clock from hardwood. When finished, the young Banneker had built the first American made clock.

In 1771, a family named Ellicott moved into the area, close to the Banneker farm, to mill wheat. One of the younger Ellicotts, George, shared Banneker's interest in math and science and the two became friends. Through George and after borrowing some books on the subject, Banneker gained a deep interest in astronomy. By 1789, after years of study, and making astronomical observations and calculations, he had acquired enough knowledge to produce tables of data providing the positions of planets and stars at future dates. These tables, called ephemerides (plural for ephemeris), were important and used at the time by sailors and navigators for determining latitude and longitude. Banneker included his ephemerides, and a variety of other information (sunrise and sunset times, weather forecasts) in an almanac. Two years later, in 1791, the first of his almanacs were published.

The same year (1791) his first almanac was published, Banneker, well known at this point for his scientific abilities, was recruited by George Ellicott to work with his cousin Andrew (an accomplished surveyor) to help survey the land site for the new U.S. capital (what was to become Washington, D.C). Banneker was stationed in an observation tent and put in charge of ensuring the accuracy of an astronomical clock and making sure the surveying team had accurate astronomical data available to them. With most of the work completed, he unfortunately fell ill and returned to his farm where he resumed work on his almanacs. For several years (until 1797), his almanacs were widely read and distributed both in the U.S. and in Europe.

Banneker was a staunch opponent of slavery and sought to disprove, by pointing to his own accomplishments, the notion that blacks were intellectually inferior to whites. When he published his first almanac, he sent a copy to then U.S. Secretary of State Thomas Jefferson and asked Jefferson (a slave owner himself) how he could justify slavery given Jefferson's own words in the constitution "...that all men are created equal." Impressed with Banneker's work and achievements, the two men started a long correspondence.

Benjamin Banneker was a true pioneering African-American scientist whose success showed what can be achieved when one is determined in their quest for knowledge, overcoming whatever obstacles that come their way.