Crni Vrh Observatory, Slovenia Comet C/1999 S4 (LINEAR) CCD Images Comet C/1999 S4 LINEAR was discovered with the Lincoln Near Earth Asteroid Research (LINEAR) telescope operating in New Mexico, USA. It passed perihelion (closest approach to the Sun) on July 26, 2000 at a distance of 0.76 AU (about 115 million km). The comet was closest to Earth almost at the same time (July 23) at a distance of ...