Comet Encke (2P/Encke) orbits from outside the asteroid belt to just inside the orbit of the planet Mercury whereas the Comet 29P/Schwassmann–Wachmann currently travels in a nearly circular orbit entirely between the orbits of Jupiter and Saturn. 2060 Chiron, whose unstable orbit is between Saturn and Uranus, was originally classified as an asteroid until a faint coma was noticed. Similarly, Comet Shoemaker–Levy 2 was originally designated asteroid . "(See also Fate of comets, above)" Centaurs typically behave with characteristics of both asteroids and comets. Centaurs can be classified as comets such as 60558 Echeclus, and 166P/NEAT. 166P/NEAT was discovered while it
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