The H.S. Mendenhall Observatory at Oklahoma State University is a premier astronomical research facility off 44th Street southwest of Stillwater. It houses the largest and most advanced telescope within 300 miles. It is a 24-inch telescope designed for astrometry, photometry and multicolor imaging of celestial objects such as near-Earth asteroids, transiting exoplanets and quasars. The observatory also features portable 8- and 14-inch telescopes for visual observing, particularly by OSU's introductory astronomy students. The facility includes a heated and cooled control building with a restroom, kitchenette, telescope control room and equipment storeroom, making it well-suited for research and instruction. Named after Harrison Shepler Mendenhall (Feb. 2, 1903-March 20, 2000), OSU's first astronomer, the observatory continues to support the academic and professional growth of students in physics, engineering and related fields.