Founded in 1888, the Rittenhouse Astronomical Society is one of the oldest astronomical societies in the United States. Named for famous American astronomer, David Rittenhouse, RAS has held regular events in the greater Philadelphia region for 133 years. We hold detailed records for nearly this entire span of time and greatly admire the astronomers and lore keepers who came before us.

We have partnerships with the Franklin Institute in Philadelphia, PA and Ryan Observatory at Muddy Run in Holtwood, PA. We encourage all those interested in the night sky to join us for our many events.

For our monthly events, we invite engaging, informative, creative professionals to speak to our members, as well as the public. Although we are currently still hosting our events on Zoom because of Covid-19, under normal circumstances, we invite attendees to sit under the wonders of a planetarium to listen to our speakers.

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