204 Kallisto is a fairly typical, although sizeable Main belt asteroid. It is classified as an S-type asteroid. Like other asteroids of its type, it is light in colour. It was discovered by Johann Palisa on 8 October 1879, in Pola, and was named after the same nymph Callisto in Greek mythology as Jupiter's moon Callisto.

Photometric measurements during 2009 produced a lightcurve that indicated a sidereal rotation period of with a variation amplitude of magnitudes. This result conflicted with previous determinations of the period, so the latter were ruled out.

  • The Asteroid Orbital Elements Database
  • Minor Planet Discovery Circumstances
  • Asteroid Light-curve Parameters
  • Asteroid Albedo Compilation