The Harlan J. Smith Telescope, a 107-inch optical instrument at McDonald Observatory on Mount Locke in West Texas, was completed in 1968 with substantial NASA assistance and named for Harlan James Smith, the observatory’s first Texas director. Built as a major research telescope, it has supported varied astronomical work, including studies of BD+17°3248, XO-1, and HIP 56948 as a close solar twin. In February 1970, vandalism damaged its primary mirror, slightly reducing its light-gathering power without harming image quality. It remained scientifically important into the 21st century, including research reported in 2021 on a supermassive black hole in the dwarf galaxy Leo I.