Derrick Pitts, lead astronomer at Philadelphia’s Franklin Institute, talks about the telescope used in the Bloom Observatory. The 10-inch refractor telescope has been around since 1934, and was built by Carl Zeiss Jena and shipped over from Germany.
Here’s more from the Franklin Institute’s web site:
The original observatory, opened in 1934, had two telescopes. The 10-inch, f/15 refractor, built by Carl Zeiss Jena, employed the latest optical and engineering techniques available in pre-World War II Germany. The 24-inch reflector telescope, manufactured by J.W. Fecker of Pittsburgh, was a convertible Newtonian/Cassegrain instrument with focal ratios of 14.4 and 7, respectively. The reflector was used for deep-sky observations, including the first recovery sighting of Comet Halley in the fall of 1985. City light pollution eventually rendered it ineffective, and the scope was moved to the Institute’s Space Command exhibit.
Bloom Observatory was renovated in 2006. Nationally-recognized telescope mechanic, Christopher Ray, of Ray Museum Studios and a professor of Mechanical Engineering from Swarthmore College, completely rebuilt the Zeiss refractor, upgrading it with modern PC-controlled DC-servo drives to achieve GO-TO pointing accuracy of better than 0.2 arc-seconds on both axes. The upgrade enables visitors to see not only the only the usual, but also thousands of faint objects (down to about magnitude 13)–despite high levels of ambient light pollution.
Joel N Bloom Observatory [FI.edu]