Comet Shoemaker–Levy 9 brought the impact sites into view for terrestrial observers a few minutes after the collisions. Two other space probes made observations at the time of the impact: the "Ulysses" spacecraft, primarily designed for solar observations, was pointed towards Jupiter from its location away, and the distant "Voyager 2" probe, some from Jupiter and on its way out of the Solar System following its encounter with Neptune in 1989, was programmed to look for radio emission in the 1–390 kHz range and make observations with its ultraviolet spectrometer. The first impact occurred at 20:13 UTC on July 16, 1994, when fragment
Astronomical symbols Ω (capital omega), which was originally a typographical substitute for the astronomical symbol. The symbols for aspects first appear in Byzantine codices. Of the symbols for the five Ptolemaic aspects, only the three displayed here—for conjunction, opposition, and quadrature—are used in astronomy. Symbols for a comet (☄) and a star () have been used in published astronomical observations of comets. In tables of these observations, ☄ stood for the comet being discussed and for the star of comparison relative to which measurements of the comet's position were made. Astronomical symbols Astronomical symbols are abstract pictorial symbols used to represent astronomical