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 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 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 only one of two surviving Zeiss Telescopes of this model. The other 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.

Open Saturdays & Sundays 12:00 – 3:00 for guided experiences.

  • Guided experiences depart by the entrance to the 3rd floor portion of the Wondrous Space exhibit. Check the Daily Schedule for Departure Times. Please note, The Holt and Miller Observatory is only accessible with the guided experiences.  
  • The type of experience conducted each day is determined by weather conditions including precipitation, extreme temperatures, or other factors that could cause damage to the telescope or create health and safety risks for guests and staff.


Buy Tickets   Reserve Member Tickets  Plan Your Visit

Solar observation through the Zeiss telescope at the Holt & Miller Observatory

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

The Philadelphia skyline, viewed from the the Holt & Miller observatory

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

The retractable roof of the Holt & Miller Observatory shelters our Zeiss refracting telescope from the elements when not in use.

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