HUT Observatory

Superb Meter-Class Telescope Transferred to the Michele and David Mittelman Family Foundation


Susan Duncan with the 95-cm Boller & Chivens telescope as formerly housed at Princeton’s FitzRandoph Observatory in New Jersey. The two finders are 6-inch f/10 refractors.

Culminating detailed planning starting in 2012, a major observatory telescope formerly used at Princeton University’s FitzRandolph Observatory in New Jersey has been transferred to the Michele and David Mittelman Family Foundation, operator of HUT Observatory in Colorado.  Built by the famed Boller & Chivens Company for Princeton in 1965, the reflecting telescope has a clear aperture of 95 cm.  Disassembly of the 25,000-pound instrument started in August, 2013, when HUT’s John W. Briggs arrived at Princeton to remove the optics, primary mirror cell, instrument rotator, and other smaller parts.  Disassembly of the major components with a crane and riggers came in a follow-up visit at the end of October.  The parts are now in storage in Alamogordo, New Mexico, and a survey is underway for a new observatory site, likely to be in New Mexico’s Sacramento Mountains near Cloudcroft.  Although construction will begin as soon as possible, the scale of the project will require time.

The telescope is carried on a massive equatorial mounting that was the Boller & Chivens standard for a 40-inch reflector.  The mounting is thus twin to instruments made for Yale, Northwestern, and Tel-Aviv Universities, among others.  Although nominally a 36-inch telescope, the instrument’s f/3.82 primary mirror was developed separately by Princeton and has an as-built clear aperture of 37 1/4 inches, or 95 cm.  The ultra-precision sidereal worm wheel (the main drive gear) has a diameter of 60 inches and, by itself alone, weighs 800 pounds.  The instrument payload capacity at Cassegrain focus is nominally 300 pounds using the counterweights provided.  A large instrument rotator with a position-angle index facilitates attachment of interchangeable instruments like cameras and spectrographs.  The mounting includes pathways for an optional coudé focus, but as originally specified for Princeton, it did not include the necessary extra optics.

The optical system is a classical Cassegrain, and the primary mirror is an early lightweight construction of fused quartz that was polished by the J. W. Fecker Company in Pittsburgh.   The f/13.14 secondary mirror is mounted in an interchangeable cage assembly that will facilitate a quick change from the Cassegrain focus to an anticipated new prime-focus CCD camera, filter, and coma-correcting lens assembly.  There is also the option of a Newtonian focus cage.  The Cassegrain focus will remain the most convenient option during general student access, for example, during educational programming already planned in collaboration with New Mexico Museum of Space History.


The 95-cm telescope with its primary mirror cell removed (in foreground) towers above the observing floor at Princeton's FitzRandolph Observatory.

The 95-cm Boller & Chivens telescope, with its primary mirror cell removed (in foreground), towers above the elevating observing floor at Princeton’s FitzRandolph Observatory.

As the instrument is little changed from 1965, a new motion control system using DC servo motors and absolute encoders will be specified and installed, exploiting the original worms.  We expect to make the telescope and its new observatory remote-accessible on the ASCOM standard using ACP software.  A variety of modern motion control packages are currently under study, including site visits to telescopes equipped with similar gear hardware, such as the MDM 1.3-meter at Kitt Peak.

Safely moving the Princeton telescope was greatly facilitated by the coincidence that, after storage for some years at Lowell Observatory, the former Northwestern University 40-inch by Boller & Chivens was moved and installed at JPL’s Table Mountain Observatory in California during September of 2013.  We were thus very fortunate being able to study closely the example of that move, as the hardware, rigging, and handling issues were essentially twin.  Handling the sensitive drive mechanisms was in fact non-trivial.

The Princeton telescope will begin its new life coming from an unusually rich astronomical heritage.  The Boller & Chivens firm was second-to-none in the world for research telescopes at the height of the Space Race.  Our lightweight primary mirror was associated with the famous Project Stratoscope II, a program of balloon-borne astronomy using unusually perfect 36-inch mirrors lifted to altitudes of 80,000 feet.  A second primary mirror, also recently acquired from Princeton by the Michele and David Mittelman Family Foundation, was the first actual flight mirror from Stratoscope II.  The Stratoscope projects were led by Professor Martin Schwarzschild (1912-1997), in close association with his colleague, Lyman Spitzer, for whom NASA’s Spitzer Space Telescope is named.  Project Stratoscope II, stepping so close to the excellent observing conditions of a true space environment, is considered a direct progenitor of Hubble Space Telescope and others in NASA’s Great Observatories Program.


Princeton's FitzRandolph Observatory, built in 1934 , was featured in Orson Welles' infamous "War of the Worlds" radio broadcast.

Princeton’s FitzRandolph Observatory, built in 1934 , was featured in Orson Welles’ infamous “War of the Worlds” radio broadcast.

The FitzRandolph Observatory that housed the Boller & Chivens was built in 1934 using stone recycled from Princeton’s older Halsted Observatory.  Then known simply as “New Observatory,” the building is now likely to be torn down, ending an era.  Both FitzRandolph and Halsted were homes to a line of particularly distinguished American astronomers including solar pioneer Charles A. Young, astrophysicist Henry Norris Russell, as well as students like Harlow Shapley, Donald H. Menzel, and others who likewise became leaders themselves.  A commemorative stone tablet familiar to all these astronomers will be preserved with the reflector.  As the telescope was disassembled in late October, it happened to be exactly the 75th anniversary of Orson Welles’ notorious 1938 radio broadcast, War of the Worlds.  Early in the broadcast, the play mentioned Princeton Observatory in what might be taken now as an amusing, if still sobering, famous cultural reference.

The final use of the 95-cm reflector at Princeton was led by the late Professor David T. Wilkinson in a collaboration with Harvard’s Paul Horowitz in an Optical Search for Extraterrestrial Intelligence (OSETI).  Wilkinson, a famed experimentalist and observational cosmologist, was posthumously honored by the naming of the profoundly productive Wilkinson Microwave Anisotropy Probe spacecraft.


Dr. Norman Jarosek disassembles the Cassegrain mirror mount inside the front end of the 95-cm telescope tube.

Dr. Norman Jarosik disassembles the Cassegrain mirror mount inside the front end of the 95-cm telescope tube.

Dr. Norman Jarosik, a veteran of Princeton’s OSETI project, kindly supported the optical disassembly at Princeton in August.  Also participating during this disassembly was Ken Launie of the Antique Telescope Society (ATS).  During the October effort for heavy rigging, HUT Observatory associates Alan and Aaron Sliski, active members of the ATS, were key participants.  Peter Abrahams, also of ATS, provided valuable knowledge leading to the discovery of Boller & Chivens mechanical drawings, specific to the Princeton Telescope, in storage at University of Wyoming’s Department of Physics and Astronomy.  Wyoming, in turn, kindly shared them.  Of particularly generous and key assistance was Ralph Nye, Head of Technical Services at Lowell Observatory, who was responsible for the original disassembly and recent installation of the Northwestern University 40-inch telescope at JPL’s Table Mountain Observatory in California.  Heath A. Rhoades, Astronomy Team Lead at Table Mountain, greatly facilitated a transfer of information from Table Mountain’s experience to our knowledge base.  Department Manager Susan Duncan at Princeton worked to facilitate the material transfer to the Foundation, with the cooperation and understanding of Professors David Spergel, Chairman, and Jim Gunn.   Early in the process, discussions with Wayne Green of Colorado’s Longmont Astronomical Society were extremely helpful.

For additional information, see:…..43..146D…47…43D

Click on the following link to see the illustrated poster paper on Boller & Chivens history presented by Don Winans and Peter Abrahams for the Historical Astronomy Division of the American Astronomical Society, 221st meeting, Long Beach, California, January, 2013:


The following image shows the actual Princeton telescope as assembled at the Boller & Chivens plant in South Pasadena, California.  The smaller telescope in the background is the Saywer 24-inch built for Whitin Observatory of Wellesley College.


Princeton in factory