Fitz-Clark Refractor

Fitz-Clark Refractor

Main Optical Tube


Lens Diameter: 13 inches
Focal Length: 182 inches
Focal Ratio: f/14

Finder Scope


Lens Diameter: 4 inches
Focal Length: 39 inches
Focal Ratio f/4
Under the smallest dome is the 13-inch Fitz-Clark refractor.   Constructed in 1861 by Mr. Henry Fitz of New York, it was the primary telescope of the original Allegheny Observatory.  The Fitz-Clark is a visual refractor, this means the lens was designed to bring yellow light to a focus it is where the human eye most sensitive.  It was at that time the third largest telescope in the world. 

The lens was stolen on July 8, 1872 and subsequently held for ransom.  Samuel P. Langley, then the director of the observatory refused to pay any money for the objective's return.   Realizing that if the ransom were paid, it would pave the way for other lens-knappings.  Professor Langley secretly met with the thief and with the agreement the the thief would remain anonymous, the lens was returned.  Unfortunately, the lens had a large scratch across the middle of it.  It was then sent to Alvin Clark to be re-figured.  Much to the amazement of the staff the returned lens was better than it was before the burglary, hence the two names.

The Fitz-Clark refractor has made many valuable contributions to science.  In 1906 it was moved to the new Allegheny Observatory where "it was made to be forever free to the people."  This telescope has been primarily used for the tour program and on occasion used to test instruments for the bigger telescopes.       

Instrumentation:  Santa Barbara Instruments Group (SBIG) ST-2000XM CCD imaging Camera mounted to a Taurus Image Tracker III, A Baader full aperture solar filter for direct viewing of the Sun, apparatus for doing solar projection, a multitude of 1.25 and 2 inch eyepieces




University of Pittsburgh
Department of Physics & Astronomy
Allegheny Observatory
159 Riverview Avenue
Pittsburgh, PA 15214

Last Modified 05/28/2003