The Franklin Institute
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The Holt & Miller Observatory houses our 10" Carl Zeiss Refracting Telescope, one of the largest historical artifacts in our collection (FI Cat. 1437). During daytime hours, this fully functioning telescope provides the opportunity to safely view the sun, including viewing solar features such as 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.



Did You Know?

When the Observatory first opened in 1934, it also featured a 24-inch reflecting telescope, which is now on display on the first floor of the museum.

Our telescope is one of only two surviving Zeiss telescopes of this model. The other one is located at the Griffith Observatory in Los Angeles.

The Holt & Miller Observatory is one of the few observatories in the country to provide optically safe, real-time, direct observation of solar activity.

Interactive Map

Floor

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Map of the fourth floor, showing the location of the Observatory.
Map of the fourth floor, showing the location of the Observatory.