| Minorplanet: | yes |
| Background: |
|
| 204 Kallisto | |
| Discovered: | 8 October 1879 |
| Mpc Name: | (204) Kallisto |
| Pronounced: | [1] |
| Alt Names: | A879 TA |
| Adjective: | Kallistoan |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.66974AU |
| Perihelion: | 2.20244AU |
| Aphelion: | 3.13704abbr=onNaNabbr=on |
| Eccentricity: | 0.17504 |
| Period: | 4.36 yr (1593.3 d) |
| Inclination: | 8.28673° |
| Asc Node: | 205.123° |
| Arg Peri: | 55.4125° |
| Avg Speed: | 18.22 km/s |
| Dimensions: | 50.36 ± 1.69 km |
| Rotation: | 19.489abbr=onNaNabbr=on |
| Abs Magnitude: | 8.89 |
| Mean Motion: | / day |
| Orbit Ref: | [2] |
| Observation Arc: | 136.52 yr (49863 d) |
| Uncertainty: | 0 |
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.