ultraviolet lasers, interstellar signaling
Using ultraviolet lasers as a method of signals between stars is an idea proposed by American electro-optical engineer Herbert F. Wischnia, a guest investigator on the OAO-3 (Orbiting Astronomical Observatory) satellite (also known as Copernicus). According to Wischnia, ultraviolet lasers would provide an effective and logical method of sending interstellar messages. "Stars with a temperature near that of our own Sun radiate very little energy in the ultraviolet," he pointed out, "so that the telescope receivers are not blinded by natural stellar radiation." He made his first scans with OAO-3 in November 1974, first turning the spacecraft's spectrometer toward Epsilon Eridani before moving on to look for UV signals from Tau Ceti and Epsilon Indi, though without success.