The Hopkins Ultraviolet Telescope (HUT) project was conceived, designed, and built by astronomers and engineers at John Hopkins University to perform astronomical observations in the far-ultraviolet portion of the electromagnetic spectrum, wavelengths of light that are inaccessible to ground-based telescopes. HUT's primary purpose was to observe wavelengths of light that are too short to be seen with the Hubble Space Telescope, although overlap was provided to allow direct comparison. The telescope flew twice aboard the space shuttle, once in December 1990 and again in March 1995, as part of a package of instruments called the Astro Observatory. HUT has been used to observe hundreds of objects, including stars, planets, and quasars. The HUT was donated to the National Air and Space Museum in 2001 and is currently part of the Explore the Universe Exhibition.