There are suitable places for stargazing near Philadelphia. Below are recommended locations and information about them:

Coudersport, PA
This park, located in north-central Pennsylvania, is one of the top stargazing spots in the eastern United States, about 4 hours from Philadelphia. It offers dark skies, allowing for clear observations of the Milky Way and various celestial bodies. 

Philadelphia, PA
This park, located in downtown Philadelphia, allows for some stargazing despite the city's light pollution. The park's wide meadow areas are particularly suitable for observations. 
Philadelphia, PA
A science museum located in Philadelphia, it offers astronomy-related exhibits and stargazing programs through the Fels Planetarium. 

When planning for stargazing, it is recommended to check the weather and moon phases, and to visit with the necessary equipment for safety.