The desired Spectral Element should be chosen. Spectral Elements include filters (
F), gratings and grisms (
G), echelles (
E), prisms (
PR), polarizers (
POL), linear ramps (
FR), quadrant filters (
FQ) and mirrors (
MIRROR). The names of the filters, gratings, grisms, and echelles include the wavelength of the approximate midpoint of the bandpass, in nanometers.
More than one element may be specified, if necessary, using these fields Choose the desired element from the list provided in Part
II of these
Instructions. They are also are described in the
Instrument Handbooks.