Prelude.

The Society is supported by volunteering members that perform all functions including those elected to serve as officers on the executive board and those appointed to its committees. It includes a concentrations of members across Philadelphia and the surrounding Delaware Valley area. Its membership spans the Mid-Atlantic Region of the United States. Some are professional astronomers, teachers, some are amateurs, and others are members supporting multiple astronomy clubs.

Students frequently visit and may join or earn a student membership with active attendance. Most attend to further their interest in astronomy. The Rittenhouse Astronomical Society truly is an astronomical society for everyone. The current executive board thanks all who assist us in this endeavor. It’s a common passion we share.

What’s In a Name?

The preeminent American scientist of his age, David Rittenhouse was at once an internationally famed astronomer, master craftsman of scientific instruments, surveyor and patriot. His mechanical models of the solar system, precision clocks, surveyor's theodolites, compasses, and optical lenses were of the highest order available in the world. Although he received little formal education and was a man of ordinary means, his genius was a primary force of colonial American achievements in science, known as the “Age of Enlightenment.”

fap166

Rittenhouse observed and recorded the transit of Venus across the sun in 1769 using his own precise surveying instrument. His records of those observations were distributed by the American Philosophical Society and brought the Society world-wide scientific recognition. His contemporaries thought so highly of him that he was their natural choice to succeed founder Benjamin Franklin as the Society's president after Franklin's death in 1790.

Check out the latest news release that was done about the Rittenhouse Astronomical Society.

Meetings and Locations.

Thanks to the generous support of The Franklin Institute, the Rittenhouse Astronomical Society meets the second Wednesday of every month at 7:15pm in the Fels Planetarium. The Rittenhouse Astronomical Society is one of the only clubs in our area that meets regularly in an amazing planetarium. As our meeting adjourns - weather permitting - we head out under the stars in the newly renovated Joel N. Bloom Observatory located on the rooftop at the institute in Center City, Philadelphia. See what it is like to use an amazing historical telescope located in Center City, Philadelphia, Pennsylvania.

Our meeting location address is:

The Franklin Institute
222 North 20th Street
Philadelphia, PA 19103


Joel N. Bloom Observatory
Joel N. Bloom Observatory