James V. Scotti are subject to non-gravitational forces due to outgassing and solar wind, it is often a challenge to predict their exact position and rediscover them each time they make a new perihelion approach). He confirmed the discovery of the well known Comet Shoemaker-Levy 9, which impacted Jupiter in July 1994. He has also discovered the periodic comets 202P/Scotti, 244P/Scotti, P/2003 L1 (Scotti), P/2010 C1 (Scotti), P/2010 H4 (Scotti), P/2010 H5 (Scotti), P/2011 A2 (Scotti); the later seven are not yet numbered as they have only been seen at one perihelion passage. He has also discovered non-periodic comets C/2010 E5 (Scotti) and
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