Step lengths for relativistic energies.
Extra care has to be taken if the energies that will be entered below are extremely relativistic. Vary the step length (either by varying the maximum step length or by varying the 'fractional inaccuracy' to be entered later, see note on ray tracing accuracy) until the message 'Energy is too relativistic -try a smaller inaccuracy or smaller step length' is on the verge of being shown, then reduce the step length by a factor of about 3 or more.
Return to general note on step lengths or times