Founded in 1888, the Rittenhouse Astronomical Society is one of the oldest astronomical groups in the United States. The society offers all interested persons an opportunity to participate in the activities of an astronomical group at the laymen's level. We aim to spread knowledge, awareness, and enjoyment of astronomy and astronomical issues. We are a popular science club that keeps its members up-to-date on the latest developments. No experience is necessary to attend.

The society met regularly in Camden, N.J. until 1931 when it began having meetings at the Franklin Institute on south Seventh Street. When the Institute moved to its present location at 20th and the Parkway in 1934, RAS did as well. 

On November 16, 1988, RAS celebrated its 100th anniversary and was honored by the City of Philadelphia with a proclamation declaring the date “Rittenhouse Astronomical Society Day.” The society has brought the cosmos to the public through a variety of presentations and guest speakers. RAS is proud to have stimulated thousands to take an interest in science.

The society was named in honor of a Philadelphia astronomer, David Rittenhouse. A surveyor and clock-maker, Rittenhouse combined his talents to become world famous for the construction of orreries and his work on the transit of Venus of 1769. 

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 concentration of members across Philadelphia and the surrounding Delaware Valley area. Its membership spans the Mid-Atlantic region of the United States.

Most all attend our public meetings to further their interest in astronomy. Some are professional astronomers, others are teachers.  Some are amateurs, and others are members supporting multiple astronomy clubs. Students frequently visit and are encouraged to attend. 

The RAS truly is an astronomical society for everyone. The current executive board thanks all who assist us in this endeavor. It is a common passion we share.