Figure 8.6: Magnetic field at the position of Hipparcos in satellite coordinates as a
function of orbital phase (± 0.5 at perigee, 0.0 at apogee) over 4 successive orbits:
the thin curves represent the field components on x and y; the thick curve is the z
component. The units are Tesla. The red, green and blue curves represent the x, y
and z axis respectively.