A pitfall in the calculation of higher order aberrations.
When calculating aberration coefficients of secondary and higher order, there is a danger of misinterpreting the result. An example is given for a homogenous magnetic field and the source of the difficulty is described.
Lencová
Bohumila
B
Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, vvi, Královopolská 147, Brno, Czech Republic.
Lenc
Michal
M
Hawkes
Peter W
PW