Although zero-order quartz waveplates are widely used in instrumentati
on that needs good temperature and field-of-view characteristics, the
residual errors associated with these devices can be very important in
high-resolution polarimetry measurements. How the field-of-View chara
cteristics are affected by retardation errors and the misalignment of
optic axes in a double-crystal waveplate is discussed, The retardation
measurements made on zero-order quartz and single-order ''achromatic'
' waveplates and how the misalignment errors affect those measurements
are discussed.