The Self-Made Man

Rittenhouse by Peale
David Rittenhouse (1732-1796) was a world renowned astronomer, scientist, mathematician, surveyor and inventor.
He was also entirely self-taught.
Rittenhouse grew up near Germantown, PA. It is said that at age 13 he had mastered Newton's laws of motion and gravity. He was one of the first Americans to build a telescope and used his to observe the transit of Venus across the sun in 1769.
Based on his observations, Rittenhouse stated that the distance between the earth and the sun was 93,000,000 miles. He was, of course, correct.

Transit of Venus
He built his home in Philadelphia where he regularly held salons attended by Benjamin Franklin and others. Thomas Jefferson said "he would rather attend one of those meetings than spend a week in Paris."
Rittenhouse proves that genius is where you find it. Jefferson's encomium, from a man who had lived in France for years and was revered by European intellectuals, underscored that America could think, too.
Rittenhouses's portraitist, Charles Wilson Peale, studied under John Singleton Copley and Benjamin West. He was around at the right time. In Philadelphia in 1776 he painted portraits of Washington, Hancock, Franklin, Hamilton and Jefferson.
Peale fought in the American Revolution, gaining the rank of Captain in the Pennsylvania Militia.
Sources: SI.edu, Wiki, National Portrait Gallery