Crowds of Franklin Institute members gather on the roof in the Holt and Miller Observatory to do some Sun gazing.

The Holt & Miller Observatory

The Holt & Miller Observatory houses the 10” Carl Zeiss Refracting Telescope, one of the largest historical artifacts in the museum's collection (FI Cat. #1437). It is only one of two surviving Zeiss Telescopes of this model. The other is located at the Griffith Observatory in Los Angeles. During select daytime hours, this fully functioning telescope provides the opportunity to safely view the Sun in real-time, including sunspots and prominences, while the rooftop location offers a unique view of the Philadelphia Skyline.

The Holt & Miller Observatory is operated and maintained by The Franklin Institute’s Chief Astronomer, Derrick Pitts.

The Holt & Miller Observatory is closed for repairs. We apologize for the inconvenience.

Solar Viewing at the Holt & Miller Observatory

Solar Viewing
Observe the sun safely through our Zeiss Refractor Telescope and enjoy views of the Philadelphia Skyline.

Skyline & Scopes at the Holt & Miller Observatory

Skyline & Scopes
View one of Philadelphia’s iconic skyline buildings through a reflecting telescope and learn about our historic observatory.

Visiting the Holt & Miller Observatory at Philadelphia's Franklin Institute

Observatory Visit
Visit the observatory and learn how telescopes work and what they can teach us about our Sun.