This week’s Pennsylvania Treasure is a solar system chart from the first half of the 19th century. The chart is hand drawn with ink and watercolors on paper and depicts 11 planets, some with moons, the sun and a comet. CAP curators Amy Frey and Rachel Lovelace-Portal chose this item as a Pennsylvania Treasure since it illustrates the fascinating story of how the planet Uranus got its name. On this chart, Uranus is labeled “Planet Herschel.”
William Herschel, a native of Hanover in present-day Germany residing in Somerset, England, discovered Uranus in 1781. Initially, Herschel believed the planet to be a comet. Other astronomers studied the orbit and confirmed Herschel’s comet to be a planet. Honored for his discovery, Herschel named the new plant Georgius Sidus, after the King George III. However, this name was not popular with astronomers outside of Britain who proposed other monikers such as Herschel and Neptune. Johann Elert Bode, a German astronomer, suggested Uranus, and by 1850 the name stuck.
The chart is not dated and we do not know exactly when it was drawn, but there are clues that provide for a possible date range. The presence of six moons around Uranus indicates that the chart was created after 1798, the year William Herschel first suggested that number (modern science has since revealed that Uranus is surrounded by at least 27 moons). In addition, the chart mentions four minor planets: Ceres, Pallas, Vesta, and Juno. These proto-planets, technically asteroids, were discovered between 1801 and 1807. The absence of the planet Neptune suggests that the chart was created sometime before 1846. Additionally, the path of the comet depicted on the chart possibly alludes to the Great Comet of 1843, which was known to have passed extremely close to sun.
We know nothing about who created the chart, where it was used or how it’s connected with the Commonwealth of Pennsylvania. Staff members discovered it in the State Museum, along with two other charts of the same style, nearly 50 years ago. At that time, no one knew how or when they came into the museum’s possession. We will continue to research this collection in an effort to uncover more details of its history.
About Pennsylvania Treasures:
In early 2012, The Pennsylvania Historical and Museum Commission launched the Collections Advancement Project (CAP), a program to inventory and catalog our vast and significant holdings of art and artifacts. These efforts are resulting in better stewardship of our collections which represent Pennsylvania arts, culture, history, sciences, business and agriculture. As a component of the project, CAP curators have researched rarely exhibited artifacts and works of art. We are sharing these Pennsylvania Treasures with the public through weekly updates.