Magnetic coordinates for the Pioneer 10 Jupiter encounter

The magnetic coordinates of the Pioneer 10 spacecraft and the five innermost satellites are given around the time of Jupiter encounter, December 1–8, 1973. The D 2 offset dipole model of Smith et al. (1974 b ) is used to make the calculations. Magnetic coordinates are needed for the interpretation of the trapped particle measurements, including the absorption effects of the satellites, reported on elsewhere in this issue. Contours of constant field magnitude and magnetic latitude are given at the surface of Jupiter for the D 2 model. The system III longitude of a spacecraft at Jupiter is derived and formulas are given for the relationships between system I, II, and III longitudes. The longitude of the magnetic dipole increases by about 3°/yr owing to the inaccurate rotation rate used to define system III longitude.