The H.S. Mendenhall Observatory

Oklahoma State University's observatory is situated under clear, dark skies southwest of Stillwater, Oklahoma. It is the home of the largest and most advanced telescope in Oklahoma and within 300 miles. Pictured at right are the dome (the first of two planned buildings) and the telescope. Visit the 24-inch Telescope Gallery to view images made with it.


The observatory's layout is derived from a conceptual design by Stanly E Black, AIA, Architect, Boston, Massachusetts. The circular fence encloses the dome and a central concrete pad for portable telescopes. The second planned building, the Control House, will occupy the three-o'clock position. There is ample space for outdoor stargazing and additional structures. Visit the Construction Photo Archive to see the observatory being built.


The observatory's smaller, first telescope was in service until May 2006. Visit the 14-inch Telescope Gallery to view images and videos showing the first telescope, the students who used it, and the objects they observed.



Control House Fundraising News

Updated June 2016


OSU's Physics Department is now submitting a work request for constructing at least the first two phases of the observatory's Control House (see the third paragraph below).


The rectangular Control House is pictured at right in the bottom illustration (copyright 2002 by Toby Wilson). It will make the observatory an outstanding research facility for students and faculty, and be a great place for public viewings. It will contain a restroom, kitchenette, telescope control room, and equipment storeroom, all heated and cooled.


The Control House will also enable OSU to offer an astronomy minor, unique in Oklahoma, that incorporates modern observatory experience. OSU students who minor in astronomy and major in physics or related fields will be ready for exciting, well-paying employment after graduation in industry, science, and defense.


The construction plan for the Control House has six phases. They are (1) exterior walls, roof, doors and windows, (2) electrical systems, (3) heating and air conditioning, (4) plumbing and septic systems, (5) interior completion, including walls, and (6) exterior completion, including sidewalk.


The estimated cost of Phase 1 is $88,000, while that of Phase 2 is $22,000. Contributions from private individuals total $116,000. A $3,000 corporate match is anticipated, and the OSU Physics Department has pledged $5,000.


The estimates for the remaining four phases are $15,000, $15,000, $22,000, and $7,000, respectively. All estimates above cover all costs, including fees and 11% contingency allowances. They can be built sequentially.


Help OSU build the observatory! Naming opportunities are available. For more information, please download the illustrated, five-page description of the Control House project in PDF format.


Please note that the National Science Foundation, National Aeronautics and Space Administration, US Air Force and other federal entities do not fund the construction of buildings — only equipment purchases and research operations.


If you would like to contribute, please click here to make an instant donation via credit card to OSU Foundation account 22-40400, or contact Dr. Peter Shull and the OSU Foundation.



The Observatory on YouTube, TV and Radio

Click here to see the observatory on YouTube. This 6-minute video includes action shots of the telescope and dome, and interviews featuring OSU's president and two students.


The observatory is also in the five-part series entitled "Wonders of the Solar System" produced by the British Broadcasting Corporation (BBC). The observatory appears 34 minutes into the second episode, "Order out of Chaos". The series premiered in 2010 in the UK and the USA, and is commercially available on DVD. To see pictures related to the BBC's visit to Stillwater in 2009, click here.


On March 2, 2010, the Oklahoma Center for the Advancement of Science and Technology (OCAST) recorded a one-hour interview about the observatory with its director that was broadcast the following weekend across Oklahoma by ten radio stations. Click here to download an MP3 file of the broadcast. The actual interview starts 15 minutes into the program.



Stillwater Clear Sky Chart

Use the Stillwater Clear Sky Chart below to view a map of expected weather conditions for the Mendenhall Observatory. First click on the chart below. In the window that then opens, clicking one of the little squares in the top row will display a map of predicted cloud cover for the corresponding date and local time.


The Stillwater Clear Dark Sky Calendar



Dr. H.S. Mendenhall

Dr. H.S. MendenhallThe observatory is named for Harrison Shepler Mendenhall, Oklahoma State University's first astronomer.


Dr. Mendenhall earned his Ph.D. in astrophysics at the University of California at Berkeley, and served on OSU's faculty as a professor of mathematics and astronomy from 1937 until his retirement in 1968. During World War II, he taught navigation to countless air cadets as a lieutenant and captain in the U.S. Army Air Corps. Dr. Mendenhall died on March 20, 2000, at the age of 97.


Dr. Mendenhall's Personal TelescopeThis photograph shows Dr. Mendenhall's personal telescope, a 4-inch refractor built in the early 1890's, set up on the central observing pad.