[Previous] | [Session 87] | [Next]
E. F. Erickson (NASA Ames Research Center), D. Rabanus (DLR-WP, Berlin)
The collimated optical beam in a grating spectrometer is often circular or elliptical in cross section, so that different parts of the beam illuminate different numbers of grooves on the grating. Here we estimate the consequent loss in spectral resolution relative to that obtained with a beam which illuminates a fixed number of grooves. For representive diffraction resolution functions, the effect is to reduce the intrinsic resolving power of the spectrometer by about 15